Question

A small wire piece of length 2 mm is bent in the form of shape L and is placed at 30 cm away in front of a concave mirror of focal length 20 cm. If both sides of L are equal then length of image formed will be –

• A. 2 mm
• B. 4 mm
• C. 6 mm
• D. 8 mm

Answer 1

Answer: (C)

6 mm

Answer 2

Transverse magnification

m = = $\frac { - 20 } { - 20 + 30 }$ = –2

Longitudinal/Axial magnification

m¢ = – m² = – 4

\ Length of image = (1 × 2) + ( 1 × 4) = 6 mm