Question

A Point object is moving uniformly towards the pole of a concave mirror of focal length 25 cm along its axis as shown below. The speed of the object is 1 $ms^{-1}$. At t = 0, the distance of the object from the mirror is 50 cm. The average velocity of the image formed by the mirror between time t = 0 and t = 0.25 s is

• A. zero
• B. $40 \, cm s^{-1}$
• C. infinity
• D. $20\, cm\,s^{-1}$

Answer 1

Answer: (C)

infinity

Answer 2

Focal length = 25 cm
$U_{f}=25 \, c m$
$V_{f}=\infty$
$=\frac{V_{f}-V_{i}}{\Delta t}=\infty.$