An object 5 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image,

(b) – 20 cm is the correct option.

(b) When an object is placed at the centre of curvature in front of a convex lens, its image is formed at the centre of curvature on the other side...

Here, R=32 cm ; f =? [convex mirror] f=R/2=32/2=16 cm.

Here, in case of concave mirror u=10 cm [u, is always negative] v =?;m = - 3 [real image] Now the magnification formula is m= -v/u or -3= -(v/-10) or , v = -30 cm. Image will...

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...

For real image of same size, the object must be placed at the distance 2f in front of convex lens, choice (b) is correct.

(c) both concave mirror and convex lens.

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 and virtual.

(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....

(a) Virtual image formed is larger in size in case of concave mirror.