11. Artificial satellites are used for a) TV transmission b) Detecting minerals c) Space research q d) All the three 12. If you walk towards a plane mirror at a speed of 10 cm/s at what speed does your images approach you ? a) 5 cm/s b) 10 cm/s c) 20 cm/s d) information inadequate 13. The phenomenon which cannot be explained by we theory is a) reflection b) refraction c) photoelectric emission d) polarization 14. Electrons can be accelerated to very high energies by means of a) thyratrons b) magnetrons c) betatrons d) cyclotrons 15. Ice is slippery, when a man walks on it, for a) its surface is smooth b) there is no friction c) increase of pressure causes ice to melt d) it is very chill 16. The sky is blue in colour because of a) the moisture present in the air b) the scattering of light by dust particles or air molecules c) combination of various lights producing blue colour d) all of these 17. Penetrating power is greater in the case of a) a - ray b) b - ray c) g - ray d) X - ray 18. A raw egg and a boiled egg of the same appearance, same size and same mass can be distinguished, without breaking, by using a) inertia of motion b) inertia of motion c) conservation of linear momentum d) conservation of angular momentum 19. The splitting of a beam of white light into its different colours is known as a) refraction b) reflection c) dispersion d) none of these 20. The unit of refractive index is a) metre b) degree c) no unit d) degree -1 Read more at www.solvedquestionpapers.com   read more »