2. Questions Bank
  3. JEE Main & Advanced
  4. Physics
  5. Ray Optics

JEE Main & Advanced Physics Ray Optics Question Bank Photometry

  • question_answer
    1% of light of a source with luminous intensity 50 candela is incident on a circular surface of radius 10 cm. The average illuminance of surface is   

    A)            100 lux                                    

    B)            200 lux

    C)            300 lux                                    

    D)            400 lux

    Correct Answer: B

    Solution :

                       \[\varphi =4\pi L=200\ \pi \]lumen.            so \[I=\frac{\varphi }{100\,A}=\frac{200\,\pi }{100\times \pi {{r}^{2}}}=\frac{2}{{{(0.1)}^{2}}}\]= 200 lux.


You need to login to perform this action.
You will be redirected in 3 sec spinner