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COMEDK2017PhysicsRay Optics

Which of the following is a wrong statement?

Options

  1. AD= 1 f , where f is the focal length and D is called the refractive power of a lens.
  2. BPower is called a clioptre when f is in metres.
  3. CPower is called a dioptre and does not depend on the system of unit used to measure f .
  4. DD is positive for convergent lens and negative for divergent lens.

Correct answer

C. Power is called a dioptre and does not depend on the system of unit used to measure f .

Step-by-step solution

The power of a lens is given by the reciprocal of its focal length, P= 1 f When f is in metre, then power P is in dioptre. Thus, power depends on the system of unit used to measure f .

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