Question

Assertion :A convex lens of glass $(\mu =1.5)$ behave as a diverging lens when immersed in carbon disulphide of higher refractive index $(\mu =1.65).$ Reason: A diverging lens is thinner in the middle and thicker at the edges.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

$\mu =\frac{{\mu }_g}{{\mu }_c}=\frac{1\cdot 5}{1\cdot 65}$ which is less than 1

$\frac{1}{f}=(\mu -1)(\frac{1}{R_1}-\frac{1}{R_2})$

$f$ becomes negative , Therefore, the lens behaves as a diverging lens.