Question

An object is placed 15 cm away from a convex mirror of focal length 45 cm. Calculate the position of the image and it's magnification.

Answer 1

Answer:

position of the image = 11.25 cm

magnification = 0.75 cm

Explanation:

given information:focal length = f = 45 cm

object distance = u = 15 cm

solution:

applying sign conventions

u = -15 cm

f = 45 cm

now 1/f = 1/v+1/u

or we can write as 1/v=1/f-1/u

substituting the values we get

1/v=-4/-45

v=11.25 cm

therefore the image is 11.25 cm behind the mirror

magnification is given by

m=h'/h=-v/u

m = -11.25/-15=0.75 cm

m = 0.75 cm

therefore the image obtained is virtual,erect and diminished by a factor of 0.75 cm

hence position of image = 11.25 cm

magnification = 0.75 cm