A convergent beam of light converges to a point 20 cm behind the convex mirror on the principal axis. An inverted image of the same size is formed coincident with the virtual object. Then, the focal length of the convex mirror is

Question

A convergent beam of light converges to a point 20 cm behind the convex mirror on the principal axis. An inverted image of the same size is formed coincident with the virtual object. Then, the focal length of the convex mirror is (A) 20 cm (B) 10 cm (C) 40 cm (D) 30 cm

Tardigrade Admin · Accepted Answer

(1/20)+(1/20)=(1/f) or (1/f)=(1/10) or f=10 cm .

Q. A convergent beam of light converges to a point $20 c m$ behind the convex mirror on the principal axis. An inverted image of the same size is formed coincident with the virtual object. Then, the focal length of the convex mirror is

20 cm

10 cm

40 cm

30 cm

$\frac{1}{20} + \frac{1}{20} = \frac{1}{f}$ or $\frac{1}{f} = \frac{1}{10}$ or $f = 10 c m .$

Q. A convergent beam of light converges to a point 20cm behind the convex mirror on the principal axis. An inverted image of the same size is formed coincident with the virtual object. Then, the focal length of the convex mirror is