Question

An object is placed 20.0 cm in front of a concave
mirror whose focal length is 25.0 cm. What is the
magnification of the object?
(a) +5.0
(b)-5.0
(c) +0.20
(d) -0.20

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Answer 1

Answer:

u=-20cm

f=-25cm

m=?

1/f=1/v-1/u

= -1/25=1/v+1/20

1/v=-1/25-1/20

1/v=-9/100

v=-100/9

m=-v/u

m= (-100/9)/(-20)

m=100/180

m=5/9