Question

A 4.5 cm long needle is placed 10 cm away from a convex mirror of focal length 16 cm. Locate the image of the needle from the mirror.

Options

• + 4.5 cm

• + 6.2 cm

• - 4.5 cm

• - 6.2 cm

Answer 1

+ 6.2 cm

Explanation:

`1/"v" + 1/"u" = 1/"f"`

∴ `1/"v" = 1/"f" - 1/"u"`

= `1/(+10) - 1/-16 = 1/16 + 1/10`

∴ v = +6.2 cm