PYQSide ExamsMy practice

Dual Nature of Radiation and Matter · Question 16

JEE Main 2026 (Online) 21st January Morning ShiftMCQMedium📈 Topic in 26% papers+4−1
1

A light wave described by E = 60 [ (3 1015 t ) + (12 1015 t ) ] (in SI units) falls on a metal surface of work function 2.8 eV. The maximum kinetic energy of ejected photoelectron is (approximately) eV. (h = 6.6 10-34 J s and e = 1.6 10-19 C)

  1. 3.8
  2. 7.8
  3. 6.0
  4. 5.1

Answer

(4) 5.1

Solution

The wave contains two angular frequencies: 1 = 3 1015 rad s-1 and 2 = 12 1015 rad s-1.

The maximum kinetic energy is given by the photons of the higher frequency:

Eph = h = h 22 = 6.6 10-34 12 10152 3.14 J

Eph = 1.26 10-18 J = 1.26 10-181.6 10-19 eV 7.88 eV

(Photons of 1 have energy 1.97 eV < 2.8 eV, so they cannot eject electrons.)

By Einstein's photoelectric equation:

K = Eph - 0 = 7.88 - 2.8 5.1 eV

Answer: (4)

JEE Main 2026 (Online) 21st January Morning Shift

Keep practising — Dual Nature of Radiation and Matter

2

A particle having electric charge 3 10-19 C and mass 6 10-27 kg is accelerated by applying an electric potential of 1.21 V. Wavelength of the matter wave associated with the particle is 10-12 m. The value of is . (Take Planck's constant = 6.6 10-34 J s)

JEE Main 2026 (Online) 21st January Evening Shift
3

An electron is released from rest near an infinite non-conducting sheet of uniform charge density '- '. The rate of change of de-Broglie wave length associated with the electron varies inversely as nth power of time. The numerical value of n is .

JEE Main 2025 (Online) 8th April Evening Shift
4

A photoemissive substance is illuminated with a radiation of wavelength i so that it releases electrons with de-Broglie wavelength e. The longest wavelength of radiation that can emit photoelectron is o. Expression for de-Broglie wavelength is given by: (m: mass of the electron, h: Planck's constant and c: speed of light)

  1. e = h i 2mc
  2. e = h 2mc ( 1 i - 1 o )
  3. e = h2mc ( 1 i - 1 o )
  4. e = h o2mc
JEE Main 2025 (Online) 7th April Evening Shift
5

A small mirror of mass m is suspended by a massless thread of length l. Then the small angle through which the thread will be deflected when a short pulse of laser of energy E falls normal on the mirror (c = speed of light in vacuum and g = acceleration due to gravity)

  1. = Emc gl
  2. = E2mc gl
  3. = 3E4mc gl
  4. = 2Emc gl
JEE Main 2025 (Online) 4th April Morning Shift
6

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R In the light of the above statements, choose the correct answer from the options given below

  1. Both A and R are true and R is the correct explanation of A
  2. A is false but R is true
  3. Both A and R are true but R is NOT the correct explanation of A
  4. A is true but R is false
JEE Main 2025 (Online) 4th April Morning Shift
7

The work function of a metal is 3 eV. The color of the visible light that is required to cause emission of photoelectrons is

  1. Red
  2. Green
  3. Blue
  4. Yellow
JEE Main 2025 (Online) 3rd April Morning Shift
8

If and K are de Broglie wavelength and kinetic energy, respectively, of a particle with constant mass, the correct graphical representation for the particle will be :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2025 (Online) 29th January Morning Shift
9

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Both (A) and (R) are true and (R) is the correct explanation of (A).
  2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
  3. (A) is false but (R) is true
  4. (A) is true but (R) is false
JEE Main 2025 (Online) 29th January Morning Shift
10

A proton of mass 'mp' has same energy 'E' as that of a photon of wavelength ' '. If the proton is moving at non-relativistic speed, then ratio of its de Broglie wavelength to the wavelength of photon is

  1. 1c Emp
  2. 1c 2Emp
  3. 12c Emp
  4. 1c E2mp
JEE Main 2025 (Online) 28th January Morning Shift
11

Which of the following phenomena cannot be explained by wave theory of light?

  1. Refraction of light
  2. Reflection of light
  3. Diffraction of light
  4. Compton effect
JEE Main 2025 (Online) 28th January Evening Shift

All Dual Nature of Radiation and Matter PYQs →

PDFDownload Dual Nature of Radiation and Matter PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All JEE Main Physics chapters