Question

Two beams (3.3 eV and 11.3 eV) illuminate a metal (work function 2.3 eV). Find the ratio of maximum electron speeds.

• A. 3
• B. 9
• C. 45660
• D. 45666

Hint:

K_max and speed relationship

Answer 1

The Correct Option is C

The maximum kinetic energy (K_max) is calculated as hν - Φ, where h is Planck's constant, ν is the frequency, and Φ is the work function. For sample A, K_max,A = 1 eV. For sample B, K_max,B = 9 eV. The velocity (v) is proportional to the square root of K_max (v ∝ √K_max). Therefore, the ratio of velocities v_A/v_B = √(K_max,A / K_max,B) = √(1 eV / 9 eV) = √(1/9) = 1/3.