Question

1. An object is kept at a distance of 20 cm from the pole of a concave mirror of focal length 15 cm. Find the position and nature of image.

Answer 1

1/F=1/v+1/u, here f= -15cm, u= -20cm, v=? , -1/15= 1/v+(-1/20) , -1/15+1/20=1/v , -4+3/60=1/v,. -1/60=1/v, v= -60cm, magnification= -v/u ,. m= -(-60)/-20, m= -3, if m is negative means image is inverted and real size of image is larger than object