Question

The image of an object placed at a distance of 30 cm from a convex mirror is formed at 10 cm from the mirror. Calculate the focal length of the mirror.​

Answer 1

Answer:

focal lenght= -7.5cm

Explanation:

u=+30 and f=-10

by applying lens formula

1/u+1/v=1/f

1/30 + 1/v = -1/10

1/v = -1/10 - 1/30 = -3/30 - 1/30 = -4/30

v = -30/4 = -7.5 cm meaning virtual and erect. And quarter the size of the object.