Question

Typical frequencies for several types of electromagnetic radiation are given below. Calculate the energy of each type of radiation. ( in J's)

(a) a gamma ray: ν = 1.70 ✕ 10²⁰ s⁻¹
J

(b) a microwave: ν = 4.82 ✕ 10¹⁰ s⁻¹
J

(c) an AM radio wave: ν = 1.78 ✕ 10⁶ s⁻¹
J

Answer 1

Energy of an electro magnetic radiation is:    E =h

Where h = planck's constant = 6.625*10^-34 J. sec

a) A gamma ray with frequency ν = 1.70 ✕ 10²⁰ s⁻¹

Energy E = 6.625*10^-34 J. sec * 1.70 ✕ 10²⁰ s⁻¹

                   = 11.3 * 10^-14 J

b) a microwave with frequency ν = 4.82 ✕ 10¹⁰ s⁻¹

Energy E = 6.625*10^-34 J. sec * 4.82 ✕ 10¹⁰ s⁻¹

                  ⁼ 31.9 * 10^-24 J

c) an AM radio wave with frequency ν = 1.78 ✕ 10⁶ s⁻¹

Energy E = 6.625*10^-34 J. sec * 1.78 ✕ 10⁶ s⁻¹

                  ⁼11.8 * 10^ -28 J