Question bank/NEET UG/Physics

NEET UGPhysicsModerateRe-NEET 2026

A ray of light with wavelength λ\lambda is incident on three different photoelectric cells namely 1, 2 and 3. The threshold wavelength of these photoelectric cells are λ1,λ2\lambda_1, \lambda_2 and λ3\lambda_3 respectively and the magnitude of stopping potentials of these cells are V1,V2V_1, V_2 and V3V_3 respectively. The relation between λ\lambda and threshold wavelengths are λ1<λ,λ2>λ\lambda_1 < \lambda, \lambda_2 > \lambda and λ3>>λ\lambda_3 >> \lambda. The correct option is:

Show answer and solution
For ejection of electron energy of incident photon should be greater than work function

ϕ=hcλ\phi = \frac{hc}{\lambda}

ϕ1=hcλ1\phi_1 = \frac{hc}{\lambda_1}

λ1<λ\lambda_1 < \lambda

ϕ1>ϕ\phi_1 > \phi

No electron will eject


V1=0V_1 = 0

By Einstein photoelectric equation


ϕ=ϕ0+eV\phi = \phi_0 + eV

λ2>λ\lambda_2 > \lambda

λ3>>λ\lambda_3 >> \lambda

ϕ>ϕ2\phi > \phi_2

ϕ>>ϕ3\phi >> \phi_3

So,
V3>V2V_3 > V_2

Source: geekyrakshit/indian-exam-questions / reneet2026-code50

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