Question

2 What is the focal length of the mirror?
(a) 3m
(b) 1.5m
(c) 6m
(d) --1.5m​

Answer 1

Answer:

6m

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Answer 2

0.24 m

Here, m=uv=−4

⇒u=4−v------------(1)

Also, ∣u∣+∣v∣=1.5

4v+v=1.5

⇒4(v+4v)=1.5

 ⇒v=1.2m

So, putting the value of v in equation (1):

 u=4−1.2=−0.3m

∴f=u−vuv

⇒f=(−0.3−1.2)(−0.3×1.2)=0.24m

0.24m