question_answer

A glass slab of width 't', refractive index \['\mu '\] is placed as shown in the figure. If the point object, moves with a speed 2 cm/sec towards the slab the observed speed by the observer will be :

A) 2 cm/sec                     

B) less than 2 cm/sec

C) greater than 2 cm/sec                    

D) \[(2/\mu )\] cm/sec

Correct Answer: A

Solution :

[a]

If          \[\frac{dx}{dt}=2\]

\[\frac{dy}{dt}=2\]