JEE Main 2026 · 8 Apr · Shift 2 · Physics Q43

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PhysicsSingle correct+4 / -1Question 43 of 75

$K_1$ and $K_2$ be the maximum kinetic energies of photoelectrons emitted from a surface of a given material for the light of wavelength $\lambda_1$ and $\lambda_2$ , respectively. If $\lambda_1=2\lambda_2$ then the work function of material is given by :

K_2+2K_1

2K_2-K_1

K_1-2K_2

K_2-2K_1

Answer and worked solution

Official answer: D

Einstein's equation. $K_1=\dfrac{hc}{\lambda_1}-\phi$ and $K_2=\dfrac{2hc}{\lambda_1}-\phi$ .

Eliminate hc/λ₁. $2K_1-K_2=-\phi$ , so $\phi=K_2-2K_1$ .

(D)

Topics:Photoelectric effect

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JEE Main 2026 · 8 Apr · Shift 2, Physics question 43