Question

7. A concave mirror produces 4 times magnified real image of an object placed at 12cm in front of it. What is the focal length of the mirror?
explain with full procedure in breif description​

Answer 1

Answer:

For the concave mirror where an object is placed it nearer at a distance of 12 cm,

object height= Ho (let)

and image height= Hi. (negative sign is due to the inverted image of the object)

also , -Hi= 4Ho.

Hi /Ho= (-4)[. since m= Hi/Ho]

so, m= (-4).

object distance ,u = (-12)cm

image distance ,v= ?

since , m= -v/u

v= -mu= - (-4)× (-12)= (-48)cm

By mirror formula,

so,. 1/f= 1/u+1/v

= 1/(-12)+1/(-48)= -/12-1/48= -5/48

so

f= -48/5cm= -9.6 cm