Monochromatic radiation emitted when electron on hydrogen

Home » Modern Physics » Dual Nature of Radiation and Matter » Question

Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The threshold frequency of the materials is :

1. 4 × 10¹⁵ Hz
2. 5 × 10¹⁵ Hz
3. 1.6 × 10¹⁵ Hz
4. 2.5 × 10¹⁵ Hz

Correct Option: C

n → 2 – 1
E = 10.2 eV
kE = E – φ
Q = 10.20 – 3.57
h υ₀ = 6.63 eV

υ₀ =	6.63 × 1.6 × 10^-19	1.6 × 10¹⁵
	6.67 × 10^-34