Question

A concave mirror forms 3 times virtual image when an object is placed at distance 8cm from it .Evaluate the position of image and focal lenght?

Answer 1

m = -v/u

v = -3u

u = -8 cm and v = 24 cm

By mirror formula;

1/v + 1/u = 1/f

1/24 - 1/8 = 1/f

1/f = -1/12

f = -12 cm