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KVPY2015PhysicsDual Nature of Matter

A 160 watt infrared source is radiating light of wavelength 50000 Å uniformly in all directions. The photon flux at a distance of 1.8 ~m is of the order of

Options

  1. A10 ~m ⁻² ~s ⁻¹
  2. B10¹⁰ ~m ⁻² ~s ⁻¹
  3. C10¹⁵ ~m ⁻² ~s ⁻¹
  4. D10²⁰ ~m ⁻² ~s ⁻¹

Correct answer

D. 10²⁰ ~m ⁻² ~s ⁻¹

Step-by-step solution

N= I h C = P (4 R² ) h c

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