JEE Advanced2025PhysicsElectromagnetic WavesActual
A cube of unit volume contains 35 10^7 photons of frequency 10¹⁵ ~Hz . If the energy of all the photons is viewed as the average energy being contained in the electromagnetic waves within the same volume, then the amplitude of the magnetic field is 10⁻⁹ ~T . Taking permeability of free space ₀=4 10⁻⁷ Tm / A , Planck's constant h=6 10⁻³⁴ Js and = 22 7 , the value of is_______
Correct answer
0
Step-by-step solution
Total energy in cube =35 10^7 hf aligned & =35 10^7 6 10⁻³⁴ 10¹⁵ & =2.1 10⁻¹⁰ ~J aligned Total energy of EM waves = B₀^2 2 ₀ volume aligned & B ₀^2= 2.1 10⁻¹⁰ 8 10⁻⁷ 1^3 & ~B ₀=22.98 10⁻⁹ ~T aligned Ans. 22.98