1. Explain, why do the stars twinkle?
Ans. When the rays of light coming from a distant star, pass through layers of air with different densities, they refract and bend towards the normal and apparent position is formed. As the different layers of air are not stationary, but continuously intermix with each other. This results in a shift in the apparent position of the star which produce twinkling effect of the stars.
2. Explain, why the planets do not twinkle?
Ans. Compared to stars, the planets are very close to us. The light coming from the planets on passing through atmosphere does suffer refraction, with the result the apparent position of the planets change. Hence, the planets do not appear to twinkle.
3. Why does the sun appear reddish early in the morning?
Ans. During sunrise, the light rays coming from the Sun have to travel a greater distance in the earth’s atmosphere before reaching our eyes. In this journey, the shorter wavelengths of lights are scattered out and only longer wavelengths are able to reach our eyes. Since blue colour has a shorter wavelength and red colour has a longer wavelength, the red colour is able to reach our eyes after the atmospheric scattering of light. Therefore, the Sun appears reddish early in the morning.
4. Why does the sky appear dark, instead of blue, to an astronaut?
Ans. The sky will appear blue only, if there is an atmosphere around the spaceship. As there is complete vacuum around the spaceship, therefore, no scattering of light takes place. Thus, the space around the spaceship (sky) appears dark.
1. Name the component of white light that deviates the least and the component that deviates the most while passing through a glass prism. Ans. Red deviates the least and violet deviates the most.
5. Why is the refractive index of atmosphere different at different altitudes?
Ans. The refractive index of atmosphere different at different altitudes because the physical conditions of the refracting medium (air) are not stationary,
6. When a light ray passes obliquely through the atmosphere in an upward direction, how does its path generally change?
Ans. In an upward direction of the atmosphere, the optical density is decreasing continuously, so when light ray passes in such direction it bends away from the normal[denser to rare].
7. What will be the observed colour of the sky on a planet where there is no atmosphere? Why?
Ans. Black. Because there is no scattering of colour of light.
8. What is an impure spectrum? Ans. A spectrum in which the bands of different colour don’t have sharp boundaries, is called impure spectrum.
9. How the dispersed colours of white light can be recombined?
Ans. This can be achieved by placing another prism in an inverted position in the path of dispersed light.
10. Define prism.
Ans. Prism is a piece of glass or any other transparent material, bounded by two triangular and three rectangular surfaces. The rectangular surface of the prism is called refracting surface. The line along which two refracting surfaces of a prism meet is called refracting edge of the prism. The angle between the two refracting surfaces of a prism is called refracting angle of the prism.
VERY SHORT QUESTIONS WITH ANSWERS (1 MARK)
(ii) No residue is left after it has burnt itself out.
i) The initial cost is high. ii) It causes displacement of people from large areas of land.
(ii) what type of mirror is used in Box Type Solar cooker?
(iii) why it is difficult to use hydrogen as a source of energy?
(iv)what is the maximum temperature attained in a concave reflector type solar cooker?
(v)Fossil fuels are classified as non-renewable source of energy. Explain why.
(iii) It cannot be stored safely as (a) it burns with explosion and(b) has low ignition temperature.
(iv) about 200oC.
(v)fossil fuels cannot be replenished. It takes millions of years for their formation.
(b) Why is the energy of water flowing in a river considered to be an indirect form of solar energy?
(c) Write one advantage of nuclear fission reaction.
Q.6. A student has set up a solar cooker in a box by using a black painted aluminum sheet, a black cooking vessel, some glass wool, a glass sheet and a mirror plate. What is the role of each item used in the solar cooker?
1. What is magnetic field?
Answer: The region around the magnet, where force of attraction or repulsion can be felt by magnetic materials, is called as magnetic field.
2. What will be the frequency of an alternating current, if its direction changes after every 0.05 s?
Answer: The time period (T) of one cycle would be = 2 x (0.05 s) = 0.1 s.
frequency, f = 1/T. Hence, f = (1 / 0.1) = 10 Hz.
3.What is the principle on which working of electric generator is based? What are its important parts?
Answer: The working of electric generator is based on the principle of electromagnetic induction.
Important parts of electric generator are armature, slip rings, brushes and field magnets.
4. Why two magnetic lines of force don’t intersect each other?
Answer: If so then at the point of intersection there will be two different directions of magnetic field which is not possible.
5. Give two methods by which we can increase the strength of magnetic field produced by a circular coil carrying current?
Answer: The two methods by which we can increase the strength of magnetic field are given below:-
1. By increasing the number of turns of wire in the coil.
2. By increasing the current flowing through the coil.
6. What are the patterns of magnetic field lines inside and outside of a solenoid? What do they indicate?
Answer: (i)The field lines inside the solenoid are parallel straight lines. This indicates that the magnetic field is uniform and is therefore, same at all points inside it.
(ii)The field lines outside the solenoid are curved lines. This indicates that the magnetic field is non-uniform.
7. What are the factors which govern the force experienced by a current carrying conductor placed in a uniform magnetic field depends?
Answer: The factors which govern the force experienced by conductor which is placed in a uniform magnetic field are:-
1. strength of the magnetic field in which conductor is placed.
2. strength of current flowing through the conductor.
3. length of conductor.
8. Distinguish between an electric motor and generator?
Answer: The major differences between an electric motor and generator are stated below:
1. It converts electrical energy into mechanical energy.
2. It needs electrical energy for its working.
3. They are used as water pumps, marble grinders e.t.c
1. It converts mechanical energy into electrical energy
2. It needs mechanical energy for its working.
3. They are used as water pumps, marble grinders e.t.c
3. Diesel generator, hydro-electric generator are the examples of it.
9. Why mostly all electrical home appliances like refrigerator, toaster etc. are provided with a wire having green insulation?
Answer: Earth wire is the insulated green coloured copper wire which is connected to a metal plate deep inside the earth near the house. It is used as a safety measure.
It is kept at zero potential by connecting it to the ground, thus, providing a low-resistance conductive path for the current.
When by electric fault, if current flows through the metallic body of electric appliance and we touch it, then current finds the lower resistance path of earth wire than our body. So, current flows through earth wire only and we remain safe.
10. Describe domestic household circuit.
Answer: From an electric pole or underground cables, we receive electric supply in our homes. Domestic electric circuit consists of three main wires.The wire with red insulation is called live wire.
The wire with black insulation is called neutral wire. Potential difference between the neutral and the live wire is 220 V.
The wire with green insulation is called earth wire. It is connected to a metallic body deep inside the earth.
According to new International Convention, insulation of live wire should be of brown colour whereas neutral and earth wires should be of light blue and green (or yellow) insulation cover.
In our homes, we receive AC electric power of 220 V with a frequency of 50 Hz.
Live wire and neutral wire maintains the p.d. of 220 V.
These wires pass through the fuse board. Fuse is specially connected with the live wire. Current rating of this fuse depends on house load.
From the fuse board, these wires pass through the electric metre. From the metre, the earth wire is locally inserted inside the ground of the house.
After the electric metre, these wires pass through the main switches and fuses in different rooms.
Depending on the power of electrical appliances, two types of fuse (5A or 15 A) are used. From the switch and fuse board, the power lines are distributed to different electrical appliances.
11. Describe about short circuiting and overloading in detail.
Answer: Short Circuiting: Short-circuiting occurs in a circuit when the live wire comes in direct contact with the neutral wire. This causes much damage to the electric appliances connected with them.
Reason of short-circuiting: When the live wire touches the neutral wire, the contact portion of the two wires behave like load and due to very low resistance of copper wire, it draws very large amount of current. In the presence of this high current, the copper wire catches fire, due to joules heating effect.
Overloading: Overloading occurs in a circuit when the current in the circuit increases abruptly. It causes overheating of the wire and might lead to the fire. It can also occur due to accidental increase in the supply voltage or on connecting too many appliances to a single socket.
12. What is an electromagnet? On what factors its magnetic field depends?
Answer: Electromagnet is a magnet formed by the magnetization of a piece of a magnetic material (such as soft iron) by inserting it into a solenoid.
The magnetic field (strength) of an electromagnet depends upon:
(i) Amount of current passing through the coil
(ii) Number of turns of the coil
(iii) Nature of core material present inside coil
13. Mention the differences between an electromagnet and a permanent magnet.
Answer: Differences between electromagnet and permanent magnet are:
1.It is temporary magnet and can be demagnetized.
2.Magnetic strength can be changed. .
3.Its polarity can also be changed.
4.It is prepared from soft iron.
1.It is a permanent magnet and cannot be demagnetized easily.
2. Its strength is fixed
3.Its polarity is fixed.
4.It is prepared from hard steel.
14. What do you understand by magnetic effect of electric current?
Answer: The phenomenon due to which, a wire behaves like a magnet when electric current is passed through it, is called as the magnetic effect of electric current.
15. Explain Maxwell's right hand thumb rule?
Answer: According to Maxwell's right hand thumb rule,
“If we hold the current-carrying conductor in our right hand in such a way that the thumb is stretched along the direction of the current, then the curled fingers give the direction of the magnetic field produced by the current”,
16. What are the properties of magnetic field due to a current through a straight wire?
Answer: The properties of magnetic field due to a current through a straight wire are:
1. The magnitude of the magnetic field produced at a given point increases as the current through the wire increases.
2. The magnetic field produced by a given current in the conductor decreases as the distance from it increases.
3. The concentric circles representing the magnetic field around a current-carrying straight wire become larger and larger as we move away from it.
4. If the direction of the current is reversed in the wire, the lines will still be circular, but the directions of the lines will be reversed, which can be verified using the compass needle.
17. Which rule is used find the direction of the force on a conductor in a magnetic field. Explain?
Answer: To find the direction of the force on a conductor in a magnetic field, a simple rule known as Fleming's left-hand rule is used.
According to Fleming's left-hand rule, if you stretch the thumb, forefinger and middle finger of your left hand such that they are mutually at right angles, If the First finger points in the direction of the field. The second finger represents the direction of the current (in the classical direction, from positive to negative), then the thumb will point in the direction of the force acting on the conductor or in the direction of the resultant motion. This rule is used to know the direction of the induced current
18. Give characteristics of magnetic field lines.
Ans: (i) They represent the magnetic field.
(ii) They are directed from north to South Pole outside a magnet and from south to North Pole inside a magnet.
(iii) The field lines are closed curves.
(iv) The strength of magnetic field in a region is determined by closeness of the field lines in that region.
(v) The closer the field lines are, greater will be the field strength and vice–versa.
(vi) No two field lines ever cross each other as it would mean two different directions of field at point of intersection, which is not possible.
(viii) The parallel lines represent the uniform magnetic field whereas converging lines or diverging lines represents the non uniform magnetic field.
19. What do you mean by electromagnetic induction?
Answer: "The process, due to which a changing magnetic field in a conductor induces a current in another conductor, is called electromagnetic induction".
20. A current through a horizontal power line flows in north to south direction.What is the direction of magnetic field (i)at a point directly below it and (ii)at a point directly above it?
Answer: (i) West to East (ii) East to West
21. A straight wire carrying electric current is moving out of plane of paper and is perpendicular to it. What is the direction and type of induced magnetic field?
Ans . Induced magnetic field will be in the form of concentric circles in the plane of paper.
22.. How can it be shown that magnetic field exist around a wire carrying current?
Ans:By using magnetic compass which, shows deflection.
23 . How can a solenoid be used to magnetise a steel bar.
Answer: By inserting the steel bar inside the solenoid and switching on electric current.
24. Can a 5 A fuse be used in wire carrying 15 A current? Why?
Answer: No, because both of them would then be ineffective in controlling the amount of current flowing.
25. Give the factors that affect strength of magnetic field at a point due to a straight conductor carrying current.
Answer: Magnitude of electric current, perpendicular distance between that point and conductor.
====================more to study=========================
Q. Where do we connect a fuse: with live wire or with neutral wire?
Ans: It is always connected with live wire.
Q. Give two uses of electromagnets.
Ans: (i) It is used in cranes for lifting heavy loads.
(ii) used in electric bells.
Q. Name any two devices which use permanent magnets.
Ans: Loudspeakers, Galvanometer, voltmeter.
Q.A current-carrying straight conductor is placed in the east-west direction.
What will be the direction of the force experienced by this conductor due to earth’s magnetic field? How will this force get affected on?
(a) reversing the direction of floe of current (b) doubling the magnitude of current.
The direction of earth’s magnetic field is from G-south to G-north. Let current
is from west to east. Therefore force is vertically upwards.
(a) By reversing the direction of current, the direction of will be reversed i.e.
(b) The magnitude of the force is doubled.
Q. An electron enters a magnetic field at right angles to it as shown in fig. The direction of the force acting on the electron will be:
(a) to the right (b) to the left (c) out of the page (d) into the page
Answer: When a conductor carrying current is placed perpendicular to the direction of magnetic field, the acting on it is given by Fleming’s left hand rule.
Since the direction of current is the same as that of the motion of a positive charge, the
direction of force acting on it when moving perpendicular to the direction of magnetic field is the same as that acting on a current-carrying conductor placed
perpendicular to the direction of magnetic field. Obviously, the force acting on an electron is opposite to that. Therefore in this case it is into the page.
Q. A coil of insulated copper wire is connected to a galvanometer. What would happen if a bar magnet is (i) Pushed into the coil? (ii) Withdrawn from inside the coil? (iii) Held stationary inside the coil?
Answer: (i) Due to change in magnetic flux linked with coil, the galvanometer shows deflection (say towards right).
(ii) Due to change in magnetic flux linked with coil, the galvanometer shows deflection (say towards left opposite to that in case one).
( ii i) As it is stationary no change in magnetic flux linked with coil, so galvanometer shows no deflection.
Q.A magnetic compass needle is placed in the plane of paper near point A as shown in Figure 13.6.
In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?
Answer: In the plane of the paper itself. The axis of the compass is vertical and the field due to the conductor is also vertical. It could result in a dip of compass needle which is not possible in this case (dips result only if axis of compass is horizontal). The deflection is maximum when the conductor through A is perpendicular to the plane of paper and the field due to it is maximum in the plane of the paper
Q. Under what conditions permanent electromagnet is obtained if a current carrying solenoid is used?
(i) The current through the solenoid should be direct current.
(ii) The rod inside is made of a magnetic material such as steel
Q. It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving (i) alpha particles, (ii) neutrons? Justify your answer.
(i) Yes, Alpha particles being positively charged constitutes a current in the direction of motion.
(ii) No. The neutrons being electrically neutral constitute no current.
Q. Meena draws magnetic field lines of field close to the axis of a current carrying circular loop. As she moves away from the centre of the circular loop she observes that the lines keep on diverging. How will you explain her observation.
Answer: Strength of the magnetic field falls as distance increases. This is indicated by the decrease in degree of closeness of the lines of field.
Q. What does the divergence of magnetic field lines near the ends of a current carrying straight solenoid indicate?
Ans: The divergence, that is, the falling degree of closeness of magnetic field lines indicates the fall in strength of magnetic field near and beyond the ends of the solenoid.
Q. What is the role of the two conducting stationary brushes in a simple electric motor?
Ans: The brushes are connected to the battery and touch the outer side of two halves of the split ring whose inner sides are insulated and attached to the axle.
Q. What is the difference between a direct current and an alternating current? How many times does AC used in India change direction in one second?
Ans: Direct current always flows in one direction but the alternating current reverses its direction periodically. The frequency of AC in India is 50 Hz and in each cycle it alters direction twice. Therefore AC changes direction 2 × 50 = 100 times in one second.
Q.What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?
Ans: Fuse is used for protecting appliances due to short-circuiting or overloading. The fuse is rated for a certain maximum current and blows off when a current more than the rated value flows through it. If a fuse is replaced by one with larger ratings, the appliances may get damaged while the protecting fuse does not burn off. This practice of using fuse of improper rating should always be avoided
Magnetic Effects Of Electric Current
(One Mark Question)
Q.1 Why does the bulk of iron fillings stick to the ends of a bar magnet and not at its centre?
Ans. Because at the ends magnetic strength is maximum and at centres magnetic strength is least.
Q.2 If the frequency of A.C. is 50 Hz. Then how many times it is changing its direction in 1 second?
Ans- 100 Times.
Q.3 What is the pattern of the magnetic field lines around a straight conductor carrying current?
Ans. Concentric circles
Q.4 If the current is flowing in the direction of advancemet of screw, then what is the direction of magnetic field lines?
Ans.In the direction of rotation of screw.
Q.5 How can you say that the magnetic field is uniform inside the solenoid.
Ans. Because field lines are parallel inside the solenoid.
Q.6 Which property of a proton will change while it moves freely in a magnetic field?
Ans. Momentum or Velocity.
Q.7 According to Flemings right hand rule, which part of right hand indicate the movement of conductor?
Q.8 If the no. of turns of a circular current carrying coil are doubled, then how will the magnetic field produced by it changes?
Q.9 In which position the force on conductor is maximum when it is placed in uniform magnetic field?
Ans. When conductor is Perpendicular to field
Q-10 Suppose you are sitting in a room facing one of the wall. An electron beam moving horizontally from your back goes towards the wall in front you and is deflected to your left, what is the direction of magnetic field in the room?
Ans. Vertically upward.
Q-11 A current through a horizontal power line flows in north to south direction.What is the direction of magnetic field (i)at a point directly below it and (ii)at a point directly above it?
Ans. (i) West to East (ii) East to West
Q-12. Electric appliances like electric –press, toaster, fans etc are connected to electric mains through three-pin plug. Why ?
Ans. Electric appliances are connected to three pin plug because heavy appliances require earth wire,so that in case of leakage of any current it goes to earth and user will not get shock. full study links
1 MARKS QUESTIONS
Ans.This will result in water logging of the soil due to which roots cannot breathe and ultimately plants will die .
1. Differentiate autotrophs and heterotrophs.
2. Glucose is incompletely oxidised to ethanol or lactic acid
3. Less energy is produced 2ATP
Respiration in animals
1.In animals respiratory organs are generally present
2.The rate of respiration is fast.
(a) CO2- from air, (b)water-from soil (c)minerals-from soil along with water.
A) Chloroplast b)guard cell c)lower epidermis d)upper epidermis
Name the two stages in photosynthesis.
Chapter 6 Life Processes Study Notes
Life Process Solved question
Life Process CBSE Guess Paper
Life Process CBSE Test Paper -1
Life Process CBSE Test Paper -2
Life Process CBSE Test Paper -3
L Life Process CBSE Test Paper -4
Life Process CBSE Test Paper -5
Metal and Non Metal solved questions for class 10
1. Why can jewellery be made out of gold and silver easily?
2. Why do diamond and graphite have different physical properties?
3. Name any one metal that does not react with dilute H2SO4 to liberate H2.
4. Write the name given to the alloy of lead and tin that which is used for welding electrical wires together.
5. Name one non–metal with metallic luster.
6. Name the various types of ores from which metals are extracted. Which type of ore is the most common for most metals and why?
7. Why are metals used for making cooking vessels? Why copper and silver are most commonly used for making cooking vessels?
8. Define minerals, ore and gangue
9. Why do metals and non–metals react? Explain with the help of an example
10. What is the need of refining? What is electrolytic refining?
1. Because gold and silver are malleable and ductile.
2. Because the arrangement of atoms in the two is different.
3. Copper or silver
6. The ores used in the extraction of metals are
(i) oxide ore (ii) sulphate ore
(iii) carbonate ore (iv) halide ore
The ores of many metals exist as oxides. This is because oxygen is very reactive element and is present in a large amount on the earth.
07 Metals are generally good conductors of heat and have high melting points. So metals can withstand high temperature without melting. Metals are malleable thus, they can be given various shapes Silver and copper are best conductors of heat and they are malleable. Hence, they are preferred for making cooking vessels
08. Minerals: The elements or compounds, which occur naturally in the earth’s crust, are known as minerals. E.g. Magnesium oxide, ferrous oxide.
Ores: At some places, minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores. E.g. Ore of iron in hematite.
Gangue: Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand etc and are called gangue. E.g. gangue present along with hematite is silicon dioxide.
09. Metals are electropositive elements and have a tendency to lose electrons and acquire a positive charge while non–metals are electronegative elements and tend to gain electrons and acquire a negative charge. By doing this both metals and non metals attain the stable noble gas configuration. For the metals and non–metals to react, the electron lost by the metal atom will have to be gained by the non metal atom. The ions formed in this way are held together by strong electrostatic forces of attraction which results in the formation of ionic compounds.
10.The metals produced by various reduction processes are not pure. They contain impurities, which must be removed to obtain pure metals. The process of purification of metals is known as REFINING.
Most widely used method for refining impure metals is electrolytic
refining. Electrolytic refining means purification of metals by electrolysis. Many metals, such as copper, zinc, tin nickel, silver, gold etc are refined electrolytically.
Click here for further study CBSE Extra Score Notes X Metals and Non Metals
1 marks questions (very short answer type question)
Q.1:- Name a metal which can be cut with a knife?
Q.2:- Which metal is the best conductor of electricity?
Q.3 Which metal is poorest conductor of electricity?
Q.4 Which metal is most ductile?
Q.5 Which metal is best conductor of heat ?
ans:- silver(and copper)
Q.6:- Which metal other than mercury is liquid at room temperature?
Q.7:- Which metal is poorest conductor of heat?
Ans:- lead (and mercury)
Q.8:- What is the nature of oxides of metal?
Q.9:- What is the nature of oxides of non- metal?
Q10:-Which non-metal conduct electricity?
Ans:-Graphite, allotrope of carbon conduct electricity.
Q.11:- Which non-metal is lusturous?
Q.12:- Why metals are hard and have high melting point?
Ans:- Because of their crystalline structure metals are hard.
Q.13:- What is an amalgam?
Ans:- An alloy of two metals in which one is mercury is called amalgam.
Q.14:- What are the constituents of solder?
Ans:- tin and lead
Q.15:- Name the green coloured compound which appears on the surface of copper utensils?
Ans:- Basic copper carbonate
2 marks questions (short answer type question)
Q.1:- What are amphoteric oxides? Give an example.
Ans:- Oxides which react with both acids as well as bases to produce salt and water are called amphoteric oxides .for example:- Al2O3 . ZnO
Q.2:- Name two metals that react with dil.HNO3 to evolve H2 gas ?
Ans:- magnesium and manganese
Q.3:- Why metals like potassium and sodium catch fire when treated with water?
Ans:- The reaction between sodium and water is so violent that the H2 gas released catches fire .
Reaction:- 2Na(s) + 2H2O(l) ----------> 2NaOH(aq) + H2(s) + heat energy
Q.4:- Why sodium is kept immersed in kerosene oil?
Ans:- This is because sodium react with air to form Na2O (sodium oxide).
Q.5:- Which gas is produced when dil. HCl is added to a reactive metal? Write the chemical reaction when iron reacts with dil. H2SO4?
Ans:- Hydrogen gas is produce when dil. HCl is added to a reactive metal.
Fe(s) + H2SO4(dil.) ------> FeSO4(aq) +H2(g)
Q.6:- What would you observe when zinc is added to a solution of iron(II) sulphate ?write the chemical reaction that takes place.
Ans:- The solution of iron(II)sulphate slowly turns to colourless and grey coloured layer of Fe is deposited on the surface of zinc metal.
Zn(s) + FeSO4(aq) -------> ZnSO4(aq) + Fe(s)
Q.7:- Why the item made of silver turns black when exposed to air?
Ans:- Hydrogen sulphide present in air react with silver and form silver sulphide which provide black colour to silver
Ag + H2S ------> Ag2S
Q. 8:- Why ionic compounds have high melting points?
Ans:- Ionic solids have crystalline structure in which there is strong interionic attraction. So large amount of energy is needed to overcome this force of attraction.
Q. 9:- What do you mean by roasting? How it is different from calcination? In which types of ores roasting is done?
Ans:- Heating an ore strongly in excess of air is called roasting. This is done to convert sulphide ores into its oxide form. Calcination is different from roasting because it is done in absence of air.
2ZnS(s) + 3O2(g) heat -------> 2ZnO(s) + 2SO2
Q10:- Define :- (i) Ore, (ii) Mineral.
Ans:- Ore:- The minerals from which an element can be extracted profitably and conveniently is called ore. E.g. - Bauxite, Al2O3.2H2O – is an ore of aluminum.
Mineral:- The compounds of elements that occurs naturally in earth‘s crust are called minerals. E.g.- Glauber‘s salt Na2SO4.7H2O; Borax Na2B4O7.10H20 are two mineral sources of Sodium.
Q.11:- Name two metals which are found in nature in the free state.
Ans:- Silver and Gold.
Q.12:- Define :- (i) Enrichment of Ores (ii) Gangue.
Ans:- (i) Removal of earthly impurities like sand, clay from an ore is called enrichment of ore.
(ii) The earthy impurities like sand, clay that are found along with an ore are called gangue or matrix.
Q.13:- Write short notes on electrolytic refining of metals.
Ans:- In electrolytic refining the impure metal is taken as anode and the pure metal is taken as cathode. These two rods are dipped in aqueous salt solution of the same metal and electricity is passed. Pure metal from anode is dissolved into the solution and equivalent amount of pure metal from the electrolyte is deposited at the cathode
Q.14:- Name the conditions which are essential for corrosion.
Ans:- (i) Presence of moisture, (ii) Presence of air.
Q.15:- What is Galvanisation? Write its use.
Ans:- Galvanisation is a method of protecting steel and iron from rusting by coating them with a thin layer of Zinc.
Short Answer Type Questions:- (3 marks)
Q.1:- Write suitable example, explain how a metal low in the activity series can be extracted?
Ans:- Metals low in the activity series are less reactive. The oxides of these metals can be reduced to metals by heating alone. For example, extraction of Mercury (Hg) from Cinnabar (HgO).
2HgS(s) + 3O2(g) heat---------> 2HgO(s) + 2SO2(g)
2HgO(s) heat ----------------> 2Hg(l) + O2(g)
Q.2:- Write three properties of ionic compounds.
Ans:- (i) Ionic compounds have high melting points. (ii) Ionic compounds are soluble in water. (iii) Ionic compounds conduct electricity in aqueous and molten state.
1. What is anodizing? What is its use?
Ans. The process of forming a thick oxide layer of aluminium oxide that makes it resistant to further corrosion.
2. What is aqua regia? What is its use?
Ans. Aqua regia is a mixture of conc. HCl and conc. HNO3 in the ratio 3:1. It can dissolve gold and platinum.
3. What do you mean by thermite reaction? What is its use?
Ans. The reaction between Iron(II) oxide Fe2O3 with Al is used to join rail track joints or cracked machine parts. This reaction is known as thermite reaction.
Fe2O3 (s) + 2Al (s) 2Fe (l) + Al2O3 (s) + Heat
4. Why active metals do not liberate H2 gas when treated with dil. HNO3?
Ans. This is because HNO3 is strong oxidizing agent. It oxidizes H2 produced to water and itself gets reduced to nitrogen oxides.
5. Sometimes the ore itself acts as a reducing agent. Give an example.
Ans. During roasting of Cu2S, the ore itself acts as a reducing agent.
2CuS (s) + 3O2(g) → 2Cu2O(s) + 2SO2(g)
2Cu2O + Cu2S → 6Cu(s) + SO2(g)
For more study material and Pdf material : Metal and Non Metal
1 MARKS QUESTIONS
1. A farmer floods his field everyday thinking that watering in this manner will result a better yield of his wheat crop. What will be the result of this action of the farmer.
Ans.This will result in water logging of the soil due to which roots cannot breathe and ultimately plants will die .
2. Name the term for transport of food from leaves to other parts of plants.
3. Which pancreatic enzyme is effective in digesting proteins?
4. Which enzyme is present in saliva breaks down starch?
5. After a vigorous exercise you may experience cramps in your leg muscles. Why does this happen?
Ans. Accumulation of lactic acid
6. Name the organelle in which photosynthesis occurs.
7. Name the type of blood vessels which carry blood from organs to the heart.
8. Name the respiratory structures of i.Mosquito ii)earth worm.
Ans.i) mosquito—System of air tubes. ii)earth worm—moist skin.
9. Write the two functions of kidneys.
Ans.Osmoregulation and excretion.
10. What are spiracles.
Ans The holes found on the lateral side of insect‘s body.
2 marks questions answer
1.Differentiate autotrophs and heterotrophs.
Ans.The organism which prepare their own food are called autotrophs for eg: green plants .
The organisms which depend on the food prepared by other organisms are called heterotrophs for eg: animals
2.Differentiate between aerobic respiration and anaerobic respiratrion.
It occurs in the presence of oxygen
Glucose is completely broken down to carbon dioxide and water.
More energy is released 38 ATP.
It occurs in the absence of oxygen.
Glucose is incompletely oxidised to ethanol or lactic acid
Less energy is produced 2ATP
3. Explain the role of the following in the process of digestion in the human body A) saliva B) trypsin
a) Saliva contains an enzyme salivary amylase which digests starch
b) trypsin.-helps in digestion of proteins.
4. What is double circulation.?
Ans..In double circulation blood goes through the heart twice during each cycle in vertebrates.
5 Write any two points of difference between respiration in plants and respiration in animals.
Respiration in plants.
Respiration in animals
6 Differentiate Holozoic nutrition and saprophytic nutrition.
In this nutrition organisms derive their food by consuming complex organic
materials by the process of ingestion and then converting the complex molecules into simpler ones to obtain nutrients. Eg. animals and human beings.
In this type of nutrition organism derive their food from the dead and decaying materials. Eg.fungi
7. Why do veins have thin walls compared to arteries?
Ans: Veins do not have thick walls because blood is no longer under pressure but blood emerges from the heart under high pressure. So arteries have thick walls
8. Where do the plants get each of the raw materials? a) CO2 b) water c) minerals
a) CO2 from air,
c)minerals-from soil along with water.
9. What do the following transport?
a)xylem b phloem c) pulmonary vein d) venacava
a) xylem-water and minerals
b) phloem- prepared food.
c) Pulmonary vein-oxygenated blood
d) vena cava -deoxygenated blood
10. Write one function each of the following components of transport system in human beings. a)arteries b) veins c)capillaries
(a) arteries- carry blood from heart to different parts of body
(b) veins-carry blood from different parts of body to the heart.
c) Capillaries-exchange of material between blood and surrounding cells.
11. a) How is fat digested in our body? b) Where does this take place?
A) fats are emulsified by bile salts. The emulsified fats are acted upon by pancreatic and intestinal lipase to form fatty acids and glycerol.
b) digestion of fats occurs in small intestine.
3 MARKS QUESTIONS
1. What is the function of epiglottis in man? Draw a labeled diagram showing the human respiratory system.
Epiglottis. It is an adjustable flap of fibro cartilage that covers glottis when food is being swallowed. Diagram of human reaspiratory system. Fig 6.9 (NCERT text book page no.104.)
3. What is known as double circulation Briefly explain the process .
Ans.It is passage of the same blood twice through the heart first on the right side, then on the left side in order to complete one cycle. It has two components ,pulmonary circulation and systemic circulation. Hint. pulmonary circulation and systemic circulation
4.How water is transported upwards in plants?
Answer: Transpiration in leaves creates pull force and osmosis creates push fore. These two forces together helps in the movement of water and minerals dissolved the leaves.
5. Name the tissue that transports the prepared food in plants . Explain the mechanism of transport of food in plants.
Ans.: phloem Hint: translocation using energy from ATP. 6Briefly describe the excretory system in human beings. Hint a pair of kidneys a pair of ureters,a urinary bladder and a urethra.
7. Describe the functioning of nephrons.
Ans: Functioning of Nephron
(i). Filtration: Filtration of blood takes place in Bowman’s capsule from the capillaries of glomerulus. The filtrate passes into the tubular part of the nephron. This filtrate contains glucose, amino acids, urea, uric acid, salts and a major amount of water.
(ii) Re-absorption: As the filtrate flows along the tubule useful substances such as glucose, amino acids, salts and water are selectively re-absorbed into the blood by capillaries surrounding the nephron tubule. The amount of water re-absorbed depends on the need of the body and also on the amount of wastes to be excreted.
(iii) Urine: The filtrate which remains after re-absorption is called urine. Urine contains dissolved nitrogenous waste, i.e. urea and uric acid, excess salts and water.
Urine is collected from nephrons by the collecting duct to carry it to the ureter.
8.What are the differences between the transport of materials in xylem and phloem hint transport in xylem:
Ans: water transport using transpirational pull Transport in phloem: food, transport using energy from ATP
9. Lymph is another type of fluid involved in transportation. Justify the statement by two reason.
1. It drains tissue fluid from the extra cellular space back into blood.
2. it takes lymphocytes and antibodies from the lymph nodes to the blood.
3. Some of the fluid from digestive tract is absorbed in the lymph and store the fluid Temporarily.
10. differentiate between osmoregulation and excretion excretion is the elimination of metabolic waste products from the body.
Ans: Osmoregulation is regulating osmotic pressure of the body fluids by controlling the amount of water and salts in the body
11. What is the function of liver in human body
ans. : Liver. Secretes bile that emulsifies fats . Bile provide alkaline medium for digestion of proteins.
For more study visit Life process extra score
CLASS 10TH SCIENCE STUDY HELP BY JSUNIL
Science is a subject that often encourages exploration to learn. It is also a subject that gives lot of scope to learn by way of practical knowledge. Students in class 9 are intrigued by the various topics that are presented to them. One of the best ways to prepare for the upcoming exams is by reviewing the previous year’s question papers and sample papers. The CBSE sample papers class 9 science 2014 helps students by giving a peek into the pattern of the question paper and test their understanding of the concepts learn in the classroom.
Class X Acid Base and Salt HOTS with solution
Acid Base and Salt Solved Question Paper-1
Acid Base and Salt Solved Question Paper-2
Acid Base and Salt Solved Question Paper-3
10th Science NCERT solutions Acid Base and Salt
For further study material visit page: Acid bases and salt for class 10
1. Chemical reaction: A chemical reaction involves a chemical change in which substances react to form new substances with entirely new properties.
Substances that react or take part in the reaction are known as reactants and the substances formed are known as products.
2. Physical change: If a change involves change in colour or state but no new substance is formed, then it is a physical change.
3. Chemical change: If a change involves formation of new substances, it is a chemical
4. Chemical equation: The symbolic representation of a chemical reaction is called a
5. Exothermic and endothermic reactions: If heat is evolved during a reaction, then such
a reaction is known as exothermic reaction. If heat is absorbed from the surroundings,
then such a reaction is known as endothermic reaction
6. Combination reaction: Combination reaction is a reaction in which two or more
substances combine to give a single product.
7. Decomposition reaction: In a decomposition reaction, a single reactant decomposes to
give 2 or more products. Decomposition reactions require energy in the form of heat,
light or electricity
8. Displacement reaction: A reaction in which a more active element displaces less active
element from its salt solution.
9. Reactivity series: The Reactivity series is a list of metals arranged in the order of
decreasing reactivity. The most reactive metal is placed at the top and the least reactive
metal is placed at the bottom.
10.Double displacement reaction: A chemical reaction in which there is an exchange of
ions between the reactants to give new substances is called a double displacement
11.Precipitation reaction: An insoluble solid known as precipitate is formed during a
double is placement reaction. Such reactions are also known as precipitation reactions.
12.Redox reaction: A reaction, in which oxidation and reduction takes place
simultaneously is known as redox reaction.
13.Oxidation: Oxidation is a chemical process in which a substance gains oxygen or loses
14.Reduction: Reduction is a chemical process in which a substance gains hydrogen or
15.During a chemical reaction, there is a breaking of bonds between atoms of the
reacting molecules to give products.
16. A chemical reaction can be observed with the help of any of the following
a) Evolution of a gas b) Change in temperature
c) Formation of a precipitate d) Change in colour e) Change of state
17. Skeletal chemical equation: A chemical equation which simply represents the
symbols and formulae of reactants and products taking part in the reaction is known as
skeletal chemical equation
for a reaction. For example: For the burning of Magnesium in the air, Mg + O2 → MgO is
the skeletal equation.
18. Balanced chemical equation: A balanced equation is a chemical equation in which
number of atoms of each element is equal on both sides of the equation i.e. number of
atoms of an element on
reactant side = number of atoms of that element on the product side.
19. As per the law of conservation of mass, the total mass of the elements present in the
products of a chemical reaction is equal to the total mass of the elements present in the
20. Decomposition reaction: In a decomposition reaction, a single reactant decomposes
to give 2 or more products. Decomposition reactions require energy in the form of heat,
light or electricity
Types of decomposition reactions:
a. Decomposition reactions which require heat are known as thermolytic decomposition
b. Decomposition reactions which require light are known as photolytic decomposition
c. Decomposition reactions which require electricity are known as electrolytic
Solved Question papers updated March Final exam
10th chemical reaction and equation Solved Test paper-01
10th chemical reaction and equation Solved Test paper-02
10th chemical reaction and equation Solved Test paper-03
10th chemical reaction and equation Solved Test paper-04
10th chemical reaction and equation Solved Test paper-05
X Chemical Reaction and Equation Assignment
Fore more material of study visit Class 10th chemical reactions and equations
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