Solved 2025 Question Paper ICSE Class 10 Physics — Question 5
Back to all questionsTwo rays PQ and RS are incident on a rectangular glass block as shown in the diagram. Observe the diagram and answer the questions that follow.
Which of these two rays will :
(a) have greater lateral displacement on emerging out of the block?
(b) travel with greater speed in the block?
(c) scatter more in the atmosphere?
(a) Angle of incidence for both the rays being same, the directions of both the rays remain same. As the refracted ray corresponding to RS bends towards the normal is more than that corresponding to ray PQ hence, the lateral displacement of the emergent ray corresponding to incident ray RS will also be more.
Diagram shows, x1 and x2 are the lateral shifts of the emergent rays corresponding to incident rays PQ and RS.
So, here x2 > x1
(b) Since, the refracted ray corresponding to incident ray PQ bends less towards the normal, hence this travels with greater speed.
(c) Speed corresponding to incident ray PQ is more than the speed corresponding to incident ray RS. So, wavelength corresponding to incident ray PQ is more than the wavelength corresponding to incident ray RS. So, RS will scatter more in atmosphere.