A real image formed by a concave mirror is 4.5 times the size of the object. If the mirror is 20 cm from the object, its focal length is

Question

A real image formed by a concave mirror is 4.5 times the size of the object. If the mirror is 20 cm from the object, its focal length is (A) (90/11) cm (B) (120/11) cm (C) (150/11) cm (D) (180/11) cm

Tardigrade Admin · Accepted Answer

Correct answer is (d) (180/11) cm

Q. A real image formed by a concave mirror is 4.5 times the size of the object. If the mirror is 20 cm from the object, its focal length is

$\frac{90}{11} c m$

$\frac{120}{11} c m$

$\frac{150}{11} c m$

$\frac{180}{11} c m$

Correct answer is (d) $\frac{180}{11} c m$

Q. A real image formed by a concave mirror is 4.5 times the size of the object. If the mirror is 20 cm from the object, its focal length is

1190​cm

11120​cm

11150​cm

11180​cm

Correct answer is (d) 11180​cm

$\frac{90}{11} c m$

$\frac{120}{11} c m$

$\frac{150}{11} c m$

$\frac{180}{11} c m$

Correct answer is (d) $\frac{180}{11} c m$