Question

write two precautions to be taken while tracing the path of a ray of light passing through a rectangular glass slab for different angles of incidence

Answer 1

(i) The glass slab should be perfectly rectangular with all its faces smooth.
(ii) While fixing the pins P₁ and P₂ or the pins P₃ and P₄, care should be taken to maintain a distance of about 5 cm between the two pins. This would help in tracing the direction of incident ray and that of emergent ray with greater accuracy.