A) 0.4 cm away from the mirror
B) 0.4 cm towards the mirror
C) 0.8 cm away from the mirror
D) 0.8 cm towards the mirror
Correct Answer: A
Solution :
[a] Mirror formula \[\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\Rightarrow \frac{1}{f}=\frac{1}{-20}+\frac{1}{(-10)}\Rightarrow f=\frac{20}{3}cm\]If object moves towards the mirror by 0.1 cm then. \[u=(10-0.1)=9.9cm.\] Hence again from mirror formula \[\frac{1}{-20/3}=\frac{1}{v'}+\frac{1}{-9.9}\Rightarrow b'=20.4\]i.e., image shifts away from the mirror by 0.4 cm.You need to login to perform this action.
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