The image produced by a concave mirror is one quarter the size of the object. If the object is moved 5 cm closer to the mirror, the image will only be half the size of the object. The focal length (in cm ) of the mirror is

Question

The image produced by a concave mirror is one quarter the size of the object. If the object is moved 5 cm closer to the mirror, the image will only be half the size of the object. The focal length (in cm ) of the mirror is (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

(1/4)=(f/x0-f) (1/2)=(f/x0-5-f) Solving above two equations, we get f=2.5 cm.

Q. The image produced by a concave mirror is one quarter the size of the object. If the object is moved $5 c m$ closer to the mirror, the image will only be half the size of the object. The focal length (in $c m$ ) of the mirror is

$\frac{1}{4} = \frac{f}{x _{0} - f}$
$\frac{1}{2} = \frac{f}{x _{0} - 5 - f}$
Solving above two equations,
we get $f = 2.5 c m$ .

Q. The image produced by a concave mirror is one quarter the size of the object. If the object is moved 5cm closer to the mirror, the image will only be half the size of the object. The focal length (in cm ) of the mirror is

41​=x0​−ff​ 21​=x0​−5−ff​ Solving above two equations, we get f=2.5cm.

Q. The image produced by a concave mirror is one quarter the size of the object. If the object is moved $5 c m$ closer to the mirror, the image will only be half the size of the object. The focal length (in $c m$ ) of the mirror is

$\frac{1}{4} = \frac{f}{x _{0} - f}$
$\frac{1}{2} = \frac{f}{x _{0} - 5 - f}$
Solving above two equations,
we get $f = 2.5 c m$ .