Class 10 Maths Oswaal Sample Paper 02(CBSE 2020)
#Sample pape2020 #OswaalSample Papers 10th Maths Oswaal Sample Paper 01(CBSE 2020) 10th Maths Oswaal Sample Paper 02(CBSE 2020) 10th Maths Oswaal Sample Paper 03(CBSE 2020) 10th Maths Oswaal Sample Paper 04(CBSE 2020) 10th Maths Oswaal Sample Paper 05(CBSE 2020) Download Files Purchase Oswaal Sample for CBSE Board Exam 2020
0 Comments
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.
CBSE Class 09 School Exam Sample Paper 2020
CBSE Sample Papers for Class 9th board exam 2020 are available here. CBSE School Exam Original Papers 2020 Download link Download study material Prepared by KV
10th Maths kv study material 2020 Download File 10th Science kv study material 2020 Download File 10th social science kv study material 2020 Download File 10th English kv study material 2020 Download File 10th Sanskrit kv study material 2020 Download File Download CBSE Sample Paper unofficially
|
Blog SeaRCH Link
All
Join Us For Update |