Solved 2024 Sample Question Paper CBSE Class 10 Science — Question 6
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(i) Explain why the refractive index of any material with respect to air is always greater 1.
(ii) In the figure below a light ray travels from air into the semi-circular plastic block. Give a reason why the ray does not deviate at the semi-circular boundary of the plastic block.
(iii) Complete the ray diagram of the above scenario when the light ray comes out of the plastic block from the top flat end.
(i) The refractive index of a medium with respect to air is given by .
As speed of light in the medium is always less than the speed of light in air, hence, the above ratio is always greater than one.
(ii) The ray enters the plastic block along the normal (perpendicular) to the surface and for normal incidence there is no deviation. Hence, the ray of light does not deviate at the semi-circular boundary of the plastic block.
(iii) Completed ray diagram of the light ray coming out of the plastic block from the top flat end is shown below:
