Question

Where should a person stand in front of a concave mirror of radius of curvature 20 cm to get a real image of his own, 2 times larger?

Options

• 80 cm

• 10 cm

• 20 cm

• 30 cm

Answer 1

20 cm

Explanation:

For concave mirror,

m = -2, f = `"R"/2 = -20/2 = -10` cm

Also for spherical mirrors,

u = `(("m" - 1)/"m")"f" = ((-2 - 1)/(-2))`(-10)

∴ u = -20 cm