Q146 / 180 · AIIMS 2007 · Physics

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

  • Correct answer
    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.

Solution

The focal length is given by \(\frac{1}{f}=(\mu-1)\left(\frac{1}{R_1}-\frac{1}{R_2}\right)\). 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.

Hence, the correct answer is option: 'A'.

Relevant Questions