Question

An object 5cm tall is placed 1m from a concave spherical mirror which has a radius of curvature of 20cm The size of the image is(a) 0.11cm(b) 0.50 cm(c) 0.55 cm(d) 0.60 cm

Answer 1

answer : option (c) 0.55cm

explanation : height of object , h = 5cm

object distance, u = -1m = -100cm

radius of curvature of concave mirror, R = 20cm

so, focal length of concave mirror, f = R/2 = - 10cm

use formula, 1/v + 1/u = 1/f

or, 1/v + 1/-100 = 1/-10

or, 1/v = 1/100 - 1/10 = -9/100

or, v = -100/9 cm

now, magnification , m = height of image/height of object = -v/u

height of image/5cm = -(-100/9)/100

height of image/5cm = 1/9

height of image = 5/9 = 0.55 cm

Answer 2

Explanation:

so answer is c option....................