Dual Nature of Matter

JEE Main level, single correct, medium

120 of 200

Question 120 of 200

In a photoelectric effect experiment a light of frequency 1.51.5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electrons emitted will be:

Show answer and solution

Answer: (C) Zero

Given, fi=f0{f}_{i}={f}_{0}. Now, f=fi2=f02f=\dfrac{{f}_{i}}{2}=\dfrac{{f}_{0}}{2}.
Since f02<f0\dfrac{{f}_{0}}{2}\lt {f}_{0} i.e. the incident frequency is less than threshold frequency. Hence, there will be no emission of photoelectrons.
Therefore, current =0=0 and no photo electrons will be emitted.

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.
See it move: Photoelectric effect and matter waves simulationDrag the sliders and watch the numbers in this question change.Revise Modern Physics firstFormula sheet, solved examples and the traps students fall into.

More Physics practice

JEE Main Physics practice question on Dual Nature of Matter (Photoelectric Effect), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.