A) 20 cm
B) 10 cm
C) 5 cm
D) zero
Correct Answer: A
Solution :
[a] The focal length of an equiconvex lens is given by \[\frac{1}{f}=\frac{2(\mu -1)}{R}\]. It is given that \[\frac{1}{f}=+5\] and \[\mu =1.5\]. Therefore, \[5=\frac{2(1.5-1)}{R}\] or \[R=\frac{1}{5}\] metre = 20 cmYou need to login to perform this action.
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