A photosensitive surface has work function hν₀. Photons of energy 2hν₀ yield maximum photoelectron speed 4 × 10⁶ m/s. If energy becomes 5hν₀, speed becomes:
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Question

A photosensitive surface has work function hν₀. Photons of energy 2hν₀ yield maximum photoelectron speed 4 × 10⁶ m/s. If energy becomes 5hν₀, speed becomes:

G1 Physics · Accepted Answer

Initially K₁ = 2hν₀ − hν₀ = hν₀ and ½mv₁² = hν₀. Later K₂ = 5hν₀ − hν₀ = 4hν₀. Therefore v₂ = √4 · v₁ = 2 × 4 × 10⁶ = 8 × 10⁶ m/s. Answer: C.