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APPLICATION OF TRIGONOMETRY(Height and Distance) 10th maths

28/10/2012

APPLICATION OF TRIGONOMETRY(Height and Distance) 10th maths test paper with answer View/Download

APPLICATION OF TRIGONOMETRY: Assignment SA-2 Class X Topic : Height And Distance    View/Download
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1.      The angle of elevation of the top of a tower, from a point on the ground and at a distance of 150 m from its foot, is 30°. Find the height of the tower correct to one decimal place.

2.      From a point P on the level ground, the angle of elevation of the top of a tower is 30°. If the tower is 100 m high, how far is P from the foot of tower?

3.      A kite is flying at a height of 75 meters from the level ground, attached to a string inclined at 60° to the horizontal. Find the length of the string to the nearest meter.

4.      If the length of a shadow cast by a pole be √3 times the length of the pole, find the angle of elevation of the sun.

5. The angle of elevation of a cloud from a point 200 meters above a lake is 30° and the angle of depression of its reflection in the lake is 60°. Find the height of the cloud.

6. (a) From a boat 300 meters away from a vertical cliff, the angles of elevation of the top and the foot of a vertical concrete pillar at the edge of the cliff are 55° 40' and 54°20' respectively. Find the height of the pillar correct to the nearest meter.
(b) From a man M, the angle of elevation of the top of a tree is 44°. What is the angle of elevation from the man of a bird perched half way up the tree?

7.      The upper part of a tree broken by wind, falls to the ground without being detached. The top of the broken part touches the ground at an angle of 38° 30' at a point 6 m from the foot of the tree. Calculate
(i) the height at which the tree is broken.
(ii) the original height of the tree correct to two decimal places.

8.      The angle of elevation of the top of a tower from a point A (on the ground) is 30°. On walking 50 m towards the tower, the angle of elevation is found to be 60°. Calculate
(i) the height of the tower (correct to one decimal place).
(ii) the distance of the tower from A.

9.      From the top of a church spire 96 m high the angles of depression of two vehicles on a road, at the same level as the base of the spire and on the same side of it are x° and y°, where tan x° = 1/4 and tan y° = 1/7. Calculate the distance between the vehicles.

10. The shadow of a vertical tower on level ground increases by 10 m, when the altitude of the sun changes from 45° to 30°. Find the height of the tower correct to one decimal place.
Answers   1. 86·6 meters   2. 173·2 m                   3. 86·6 m      4. 30° 5. 400 m 6. (a) 21 m (b) 25° 46'      7. (i) 4·77 m (ii) 12·44 m    8. (i) 43·3 m (ii) 75 m 9. 288 m      10. 13·7 m

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Class –IX Surface area and Volume Guess Paper

23/10/2012

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Class – IX Surface area       Subject - Mathematics
  [Section (A)] 5 x 1 =5
1.Find the curved surface area of a cone having slant height 10 cm and circumference of base is 44 cm.
2. Find the total surface area of a sphere having diameter 14 cm.
3. Three cubes each of side 5 cm are joined end to end. Find the surface area of the resulting cuboids.
4. A rectangular sheet of paper 44 cm x 18 cm is rolled out along its length and a cylinder is formed. Find the radius of the cylinder formed.
5.The inner diameter of the well is 3.5 m and 10 m deep find:
Inner curved area
[Section (B)] 5 x 2 = 10
6.      A hemispherical bowl made of brass has inner diameter 10.5 cm. find the cost of tin painting it on the inside at the rate of Rs 16 per 100 cm square.
7.      The height of a cone is 16 cm and its base radius is 12 cm. find the curved and total surface area of the cone. Use, π = 3.14.
8.      Find the lateral surface area of a closed cylindrical patrol storage tank that is 4.2 m in diameter and 4.5 m high.
9.      The radius and slant height of a cone are in the ratio 4:7. If it’s curved surface area of this cone is 792 cm2. Find its radius. ( use p = 22/7)
The diameter of the moon is one third of the earth. Find out the ratio of the surface area of the moon and earth.
[Section (C)] 2 x 5 = 10
10. A wooden toy in the form of cone surmounted on a hemisphere. The diameter of the base of the cone is 6 cm and height is 4 cm. find the cost of painting the toy at the rate of Rs 5 per 1000 cm2
11. A heap of wheat is in the form of a cone whose diameter is 10.5 m and height is 3 m. The heap is to be covered by canvas to protect it from rain. Find the area of the canvas required.          Or
A storage tank consists of circular cylinder with a hemisphere adjoined on either end. If the external diameter of the cylinder is 1.4 m and its length be 8 m. find the cost of painting it on the outside at the rate of Rs. 10 per m2.

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6th Electricity and Circuit MCQ'S based on NCERT/CBSE

22/10/2012

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Class VI LESSON: ELECTRICITY AND CIRCUIT MCQ’S
Choose the correct answer from the bracket.

1. In electric bells electric energy transform in to ____________energy.

(a)Mechanical energy (b) Magnetic energy (c) Sound energy (d) Light energy

2. ----------- is the positive terminal of an electric cell.

(a) Metal disc (b) Metal case (c) Metal cap (d) Metal base

3.The tiny coiled metal wire present inside the bulb is called____________.

(a) Element (b) Conductor (c) Filament (d) None of these

4. A combination of two or more electric cells is called___________.

(a) Electric circuit (b) Battery (c) Terminals (d) None of these

5. An electric bulb has ____________terminals.

(a) 3 (b) 4 (c) 1 (d) 2

6 ----------- is an electric device which easily closes or opens an electric circuit.

(a) Filament (b) Electric bulb (c) Electric switch (d) Electric cell

7. A material which does not allow the electricity to pass through it is___________.

(a) Conductor (b) Electric cell (c) Insulator (d) None of these.

8. Non metals like __________and __________are conductors of electricity.

(a)Wood and paper (b) Graphite and gas carbon (c) Glass and rubber (d) None of theses

9. A material which allows the electricity to pass through it is ________.

(a) conductor (b) Insulator (c) Transistor (d) None of these

10. Electric energy is produced from the____________ within the cell.

(a) Chemicals (b) Metals (c) Terminals (d) None of these

ANSWER KEY FOR ELECTRICITY & CIRCUITS
1)B 2)C 3)C 4)B 5)D 6)C 7)C 8)B 9)A 10)A
Visit given links for further study:Solved Questions 1 to 10 visit link:
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Solved Questions 11 to 21 visit link:
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6th Electricity and Circuit CBSE Test paper-1
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6th Electricity and Circuit CBSE Test paper-2
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10th Light Reflection and refraction and Human eyes and Colorful World

20/10/2012

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CBSE Class IX ( 9th) Science | Chapter 3. Atoms And Molecules

18/10/2012

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Does every time when H2 and O2 combine, form only water?

Not every time. The product of any reaction depends on the condition the reactions i.e. temperature, pressure, catalyst etc... 2H2+O2→2H2O (water)

Apart from water, H2 and O2 combine to form hydrogen peroxide(H2O2) also.

H2+O2→H2O2 (hydrogen peroxide)

The mass of a particular substance is remain same even 1 mole of atom or 1 molecules of of any substance contains 6.022 ×10 23 atom /molecules justify?

Atomic mass or molecular it is expressed in g mol-1 i.e. it is the mass of 1 mole (6.03x1023) of atoms or molecules which is always a fixed quantity.

For example..

Molecular mass of H2O is 18 g

i.e. mass of 1 mole (6.03x1023 ) water molecule = 18g

Mass of 1 water molecule = 18/6.03x1023 = 2.988 x 10-23 g

And
We know that 1 g = 1/ 1.66 x10-24 amu

So
2.988 x 10-23 g =(2.988 x 10-23 g) /1.66 x10-24 amu = 18 amu or 18 u

What is atomicity?

Atomicity of ion may be defined as the number of atom present in that ion .

For example..

·         Al3+ atomicity is 1.

·         O2 - atomicity is 2.

Atomicity is the number of atoms of an element present in one molecule of that element.

For example, there are 2 atoms of hydrogen present in H2 molecule. So its atomicity is 2.

The gases can be

Monatomic, example: Helium (He)Carbon (C)

Diatomic, example: hydrogen (H2)

tri atomic , example: ozone (O3)

Polyatomic, example: sulphur (S8).

Give some examples of non ionic compounds?

Non ionic compounds...

CO2, C6H12O6, C6H6, CH4

How does the seventh postulate of Dalton's satisfy laws of constant proportional?

The seventh postulate of Dalton's law states that In a given compound, the relative number and types of atoms are constant.

The above statement means that the number of atoms of different elements in a compound is fixed and does not vary. We can say that the composition of a compound is fixed as same atoms will always combine in the same ratio.

Thus a molecule of water will always have 2 atoms of hydrogen and one atom of oxygen.

Remember: The postulate of Dalton’s atomic theory that “atoms can neither be created nor be destroyed” was a result of the law of conservation of mass.

What is the mass of 0.5 mole of Cl2 gas?

Molecular mass of Cl2 = 2 x atomic mass of Cl = 2 x35.5 =70 u

Mass = molar mass x number of moles= 70u x 0.5 = 35.5 u
NCERT Solutions for CLass 9th Science
IX Chapter For Science Test Paper And Study Materials links
Chapter: 3  Atoms and Molecules

Chapter:4  Structure of the Atom
YOU MUST VISIT THIS USE FULL LINK
9th chemistry Self-evaluation on Mole concept
Numerical based on mole concept
9th Chemistry Atoms and Molecules MCQ
9th CBSE Science Chap 3 Atoms and Molecules Self study
9th Atoms and Molecules - Mole Concept and Problem
9th Atoms and Molecules Downloads

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Work, Energy And Power-CBSE Questions with solution

16/10/2012

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Q.1. Can kinetic energy of a body be negative?

No as m ass and velocity cannot ne negative

Q.2. A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?

A freely falling object just before hitting the ground has maximum kinetic energy. After falling, it rolls on the rough ground and finally comes to rest. The kinetic energy of the object is used up in doing work against friction; which finally appears as heat energy.

Q.3. Find the energy in kWh consumed in 10 hours by four devices of power 500 W each.

Energy consumed = Power x time taken = 2000W x 10 h = 20000 Wh = 20 kWh.

Q.4. Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?

The work required to be done to stop a car = ( ½ mu2) - ( ½ mv2)= ½ m(u2-v2)= 1/2x1500(602-0)=2.08J

Q.5 What is the work done by the force of gravity on a satellite moving round the Earth? Justify your answer.
The work done by the force of gravity on a satellite moving around the Earth is zero.

When a satellite moves around the Earth in a circular path, then the force of gravity acts on it directed towards the centre. The motion of the satellite is in the horizontal plane. Therefore, the force of gravity of Earth on the satellite and the direction of motion of satellite are perpendicular to each other. Therefore, net work done = Fs cos 90 = 0.

Q.6. The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?

During the free fall of the object, there is continuous decrease in potential energy. This decrease in potential energy appears as an equal amount of increase in kinetic energy. Thus, the sum of the potential energy and kinetic energy of the object would be the same at all points. That is, potential energy + kinetic energy = constant.

According to the law of conservation of energy, the total energy of system remains unchanged. Thus, the given statement does not violate the law of conservation of energy.

Define 1 J of work.

Work done = Force x Displacement
If force, F = 1 N and displacement, s = 1, m then the work done by the force will be 1 Nm or1 J. Thus, 1 J is the amount of work done on an object when a force of 1 N displaces it by 1 m along the line of action of the force.

Download other study material on Work, Energy And Power

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6th : Motion and Measurement of Distances Questions with Solution

13/10/2012

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1. Describe at least three rules of measuring length correctly.

Ans: a. The scale that you are using to measure the object must be greater than the length of the object.

b. The eye should be placed just above the points that you are reading otherwise there will be error due to parallax.

c. If the zero mark of the scale is damaged or edge of scale is not smooth, then start measuring from another mark.

2. Name two devices used to measure length.

Ans: The two devices that can be used to measure length are:- Metre scale ad Screw gauge.

3. Describe the correct method of measurement of length.

Ans: (i) we must choose a suitable device for measuring the length of an object, like measuring scale

(ii) we should place the scale in contact with an object along its length and align the zero mark of the scale with the starting position of the object.

(iii) While taking the reading, eye must be placed vertically above the point where the measurements have to be taken; otherwise there will be an error in the reading which is taken due to parallex.

(iv) if the zero mark on the scale is damaged, then start the measurement from another mark.

4. Circle odd one

(a)Table; fan; falling stone; Parked car

(b)Bee ; butterfly; Grazing Cow; Sleepy Donkey

(c)Pendulum; Earth revolving around the Sun; Moon revolving around the earth; Bee revolving on flowers

(d)Moving fan; merry go round; A bus moving on road; a stone moving along circular track

Ans: (a) falling stone (b) Sleepy Donkey (c) Bee revolving on flowers (d) A bus moving on road

5.Fill in the blanks

1.One meter is --------------cm

2.one centimeter is -----------------mm

3. Four km is ---------m

4. The motion of moving bicycle is ----------------

5. The motion of drill machine is ----------

6. Motion of child on swing -------------

7. The motion of a top is ----------

Ans: 1. 100 2. 10 3. 4000 4. Rectilinear 5. rotatory 6. oscillatory
7. rotatory

6. Say true or false

(a)Rectilinear and curvilinear cannot happen at the same time

(b)Rupa can move in rectilinear and rotationary motion at the same time

(c)A child on swing has only circular motion

(d) Periodic motion is always rectilinear

(e) A foot step is used as a standard unit of length.

Ans: (a)False (b)True (c) False (d) False (e)False

Hots questions:

1. Can an object be in motion and rest simultaneously for different observer? Give an example and consequence?

Ans: Yes. A person driving a car is in rest with respect to other person in car but in motion with respect to a person standing road side. Tate of motion and rest depend on the observer or a fix point called reference point.

2. Can a body be in translational and rotational motion? Give some examples

Ans: yes, combination of translation and rotation is rolling motion like the motion of the wheel , the motion of the earth, drilling.

3. Why do we need standard unit of measurements for a quantity?

Ans: The unit used like hand span ,foot, cubit differ from person to person or even in different countries so for a uniform measurement we need standard unit of measurements.

4. Is it correct to say all periodic motion are oscillatory motion and all oscillatory motion are periodic. Give reason for answer?

Ans: In oscillatory motion body repeat its action in equal interval of time so, all periodic motion are oscillatory motion and vice versa. For example motion of swing, pendulum, motion of earth on its axis.

Post related to this chapter:
Short Questions and Solution : Motion and Measurement of Distances
Long Questions and Solution : Motion and Measurement of Distances
VI 6th Science Assignments:: CH-6 Measurement and Motion

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CBSE Maths Chapter 10: Tangents to a Circle downloads

12/10/2012

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Points to Remember :
1. Tangent to a circle at a point is perpendicular to the radius through the point of contact.
2. From a point P, lying on the circle, one and only one tangent can be drawn to it.
3. From a point, lying outside a circle, two and only two tangents can be drawn to it.
4. The lengths of the two tangents drawn from an external point to a circle are equal.
5. If two circles touch internally or externally, the point of contact lies on the straight line through the two centers.

NCERT Solution X Ch-10 - Circles by topper learning
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10th Chapter : Tangent of Circle CBSE Test Paper-1
10th Chapter : Tangent of Circle CBSE Test Paper-2
10th Chapter : Tangent of Circle CBSE Test Paper-3
10th Chapter : Tangent of Circle CBSE Test Paper-4
10th Ch:Tangent of Circle CBSE Test Paper Solved -1
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Physics: IX Work, Energy and Power

11/10/2012

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Physics: IX Work, Energy and Power Study notes and CBSE Guess and Test Paper also download Numerical
Work : Product of magnitude of force and the magnitude of displacement of the body during time in which force acts is called work. Work is a scalar quantity.

If W, F and s indicate work, force and displacement respectively then the work is given by the following formula. W = F s

SI unit of work is newton metre (Nm) which is also known as joule in memory of famous physicist Joule.

Thus, for work to be done, action of force is necessary as well as displacement in the direction of force is also necessary.

What will be the work done if angle between the force and displacement is 900 ?
Ans: work done is zero

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Physics: IX Work, Energy and Power
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WORK POWER ENERGY QUESTIONS & ANSWERS FOR CLASS XI CBSE View

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IX Numerical Problems from Pressure, Density and Flotation Physics for class 9th

8/10/2012

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Q. a cube of mass 1kg with each side of 1cm is lying on the table. find the pressure exerted by the block on the table. take g=10 m/s2
Ans: Pressure is given as force/area so, Force, F = mg = 1000 X 981 gm.m/s2and area, A = 1x1 cm2 = 1 cm2Thus, the pressure exerted would be P = (981 X 1000) / 1 or
P = 9.81 X 10 5 pa
Q. The mass of a solid iron cube of side 3cm is to be determined usig a spring balance. If the of iron is approximately 8.5 g/cm3, the best suited spring balance for determining weight of the solid would be of
1. range 0-250gwt ; least count 1gwt
2. range 0-250gwt ; least count 5gwt
3. range 0-1000gwt ; least count 5gwt
4. range 0-1000gwt ; least count 10gwt
Ans: Edge=3 cm , Density=8.5 g/cm3Mass= density x volume = 8.5 x(3x3)=229.5gwt

Therefore second spring balance of range 0-250 gwt with least count 5gwt will be suitable.
Q. The density of turpentine oil is 840 Kg/ m3. What will be its relative density. (Density of water at 4 degree C is 10 cube kg minus cube)
Ans:Relative Density = Density of Substance/ Density of water at 4 0cDensity of turpentine oil = 840 kg/ m3 ( given).Density of water at 4 0c = 1000 kg/ m3Relative density of turpentine oil = Density of turpentine oil / Density of water at 4 0c= (840 / 1000 ) kg m-3/ kg m-3 = 0.84Since, the relative density of the turpentine oil is less than 1, therefore it will float in water.
Q. A solid body of mass 150 g and volume 250cm3 is put in water . will following substance float or sink if the density of water is 1 gm-3?
Ans:
Visit link for full question solved for 9th CBSE board

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<<Previous

APPLICATION OF TRIGONOMETRY(Height and Distance) 10th maths

Class –IX Surface area and Volume Guess Paper

6th Electricity and Circuit MCQ'S based on NCERT/CBSE

10th Light Reflection and refraction and Human eyes and Colorful World

CBSE Class IX ( 9th) Science | Chapter 3. Atoms And Molecules

Work, Energy And Power-CBSE Questions with solution

6th : Motion and Measurement of Distances Questions with Solution

CBSE Maths Chapter 10: Tangents to a Circle downloads

Physics: IX Work, Energy and Power

IX Numerical Problems from Pressure, Density and Flotation Physics for class 9th

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