An object is lying at a distance of 90 cm from a concave mirror of focal length 30 cm. The position and nature of image formed by it will be

Question

An object is lying at a distance of 90 cm from a concave mirror of focal length 30 cm. The position and nature of image formed by it will be (A) 45 cm, of the size of object (B) 90 cm, smaller than object (C) 30 cm, bigger than object (D) - 45 cm, smaller than object

Tardigrade Admin · Accepted Answer

v =( uf / u - f )=(-30 ×-90/-90+30) =-(30 × 90/60)=-45 cm ( Real ) m =-( v / u )=-[(-45/-90)]=-(1/2) (small size)

Q. An object is lying at a distance of $90 c m$ from a concave mirror of focal length $30 c m$ . The position and nature of image formed by it will be

45 cm, of the size of object

90 cm, smaller than object

30 cm, bigger than object

- 45 cm, smaller than object

$v = \frac{u f}{u - f} = \frac{- 30 \times- 90}{- 90 + 30}$
$= - \frac{30 \times 90}{60} = - 45 c m ($ Real $)$
$m = - \frac{v}{u} = - [\frac{- 45}{- 90}] = - \frac{1}{2}$ (small size)

Q. An object is lying at a distance of 90cm from a concave mirror of focal length 30cm. The position and nature of image formed by it will be