Question

A boy of height 1m stand infront of convex mirror. His distance from the mirror is equal to its focal length. What is the height of his image?

Answer 1

u = −f
from the mirror formula:
1/f= 1/u+ 1/v
1/f= −1/f+1/v
1 /v= 1/f+1/f = 2/f
v =f/2
Now, since, m=hfinal/hinitial=− v/u hfinal/1=−( f/2)/−f
hfinal = 1/2×1 = 0.5m