Question

where will be the image formed when a point object is placed at a distabce of 20cm from a convex mirror of focal length 20cm

Answer 1

$\huge {\underline{\pink{Given:-}}}$

• Object distance ,u = -20cm

• Focal length ,f = -20cm

$\huge {\underline{\green{To Find:-}}}$

• Image distance ,v

$\huge {\underline{\blue{Solution:-}}}$

Note:- Focal length of Convex mirror is taken as Negative while Focal length of Concave mirror is taken as positive .

We have to calculate the Image distance so using mirror formula

• 1/v + 1/u = 1/f

where,

v is the image distance

u is the object distance

f is the focal length.

Substitute the value we get

➱ 1/v + 1/(-20) = 1/(-20)

➱ 1/v - 1/20 = -1/20

➱ 1/v = 1/20 -1/20

➱ 1/v = 1-1/20

➱ 1/v = 0/20

➱ v = 20/0 = infinity

Therefore, the image formed at infinity . The image formed is highly enlarged and virtual .