Question

Assertion : Goggles have zero power.
Reason$\quad$: Radius of curvature of both sides of lens is same

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

The focal length is given by
$\frac{1}{f}=\left(\mu-1\right)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right).$
For goggle lenses, both sides are curved the same way. $R_1$ and $R_2$ are positive. If they are the same, $\frac{1}{f}=0$ i.e. power is zero.