KVPY2014PhysicsDual Nature of Matter
A 160 watt light source is radiating light of wavelength 6200 0 A uniformly in all directions. The photon flux at a distance of 1.8 ~m is of the order of (Plank's constant .6.63 10⁻³⁴ ~J - s ) :
Options
- A10² ~m ⁻² ~s ⁻¹
- B10¹² ~m ⁻² ~s ⁻¹
- C10¹⁹ ~m ⁻² ~s ⁻¹
- D10²⁵ ~m ⁻² ~s ⁻¹
Correct answer
C. 10¹⁹ ~m ⁻² ~s ⁻¹
Step-by-step solution
array ll & N 4 R ² & ~N = 160 6200 10⁻¹⁰ 6.62 10⁻³⁴ 3 10⁸ & = 5 10¹⁹ 10 4 3.14 3.24 & = 16 62 10⁻⁷ 20 10⁻³⁴ 10⁸ & = 5 10¹⁹ 10 4 3.14 3.24 & = 496 10 10¹⁹ & =1.25 10¹⁹ array