Given, u=-10 cm, f=+15 cm,v=?
From mirror formula, 1/f=1/v+1/u
or 1/v=1/f=1/u
=1/v=1/15=1/(-10)=1/15+1/10=(2+3)/30
or v=30/5=+6 cm
That is image is formed at a distance of 6 cm from the mirror behind it. The image is erect...
Radius of curvature of convex mirror, R = 30 cm.
Focal length of convex mirror, f=R/2=30cm/2=15cm
Now h=5cm,u=-20cm,v=?,h'=?
Using the mirror formula 1/f=1/u+1/v, we have
1/v=1/f=1/u=1/15=1/-20=1/15+1/20=(4+3)/60
v=60/7=8.6cm.
Thus, image is formed at a distance of 8.6cm...
(d) 15 cm behind the mirror.
EXPLANATION:
The option can be selected by suitable reasoning. In a convex mirror, the object at infinity has its image at the focus behind the mirror....