Light of incident frequency three times the threshold frequency is incident on a photo sensitive material. If the incident frequency is made (1/3)rd and intensity is doubled then photoelectric current will (a) be zero (b) be halved (c) be increased (d) be decreased

Answer: (a). Initially ν = 3ν₀; new frequency ν' = (3ν₀)/(3) = ν₀. At the threshold, KEmax = hν₀ - φ = 0: electrons are not emitted with any energy, so no photocurrent flows. Increasing intensity cannot help when frequency is not above threshold. So the answer is (a) be zero.

Light of incident frequency three times the threshold frequency is… | MHT CET 2026 (20 May, Shift 1)

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Photoelectric Experiment: Intensity, Stopping Potential & Graphs

Light of incident frequency three times the threshold frequency is incident on a photo sensitive material. If the incident frequency is made $\left(\frac{1}{3}\right)^{rd}$ and intensity is doubled then photoelectric current will

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Answer: (a)

Initially $\nu = 3\nu_0$ ; new frequency $\nu' = \frac{3\nu_0}{3} = \nu_0$ .
At the threshold, $KE_{max} = h\nu_0 - \phi = 0$ : electrons are not emitted with any energy, so no photocurrent flows.
Increasing intensity cannot help when frequency is not above threshold.
So the answer is (a) be zero.

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Photoelectric Experiment: Intensity, Stopping Potential & Graphs question from MHT CET 2026 (20 May, Shift 1)

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