NEET Dual Nature of Radiation and Matter PYQ practice sheet

14 previous-year NEET Physics questions from Dual Nature of Radiation and Matter, newest papers first. Dual Nature of Radiation and Matter carries 16 of the Physics questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

Practise all 14 online

1.
RE-NEET 2026
A beam of light falls on a metal surface such that photo-electrons are generated. If power of the light source starts to decrease linearly with time $t$ , then variation of the photocurrent $I$ and magnitude of the stopping potential $|V|$ with time is best represented by: Each option shows two graphs: $I$ versus $t$ (left) and $|V|$ versus $t$ (right).
- (A)
- (B)
- (C)
- (D)
2.
RE-NEET 2026
A ray of light with wavelength $\lambda$ is incident on three different photoelectric cells namely 1, 2 and 3. The threshold wavelength of these photoelectric cells are $\lambda_1$ , $\lambda_2$ , and $\lambda_3$ , respectively and the magnitude of stopping potentials of these cells are $V_1$ , $V_2$ and $V_3$ , respectively. The relation between $\lambda$ and threshold wavelengths are $\lambda_1 < \lambda$ , $\lambda_2 > \lambda$ and $\lambda_3 \gg \lambda$ . The correct option is:
- (A)
  $V_1 > V_2,\; V_3 = 0$
- (B)
  $V_1 = 0,\; V_2 < V_3$
- (C)
  $V_1 = 0,\; V_2 > V_3$
- (D)
  $V_1 < V_2,\; V_3 = 0$
3.
RE-NEET 2026
A photon and an electron, each of $20$ eV energy, move in free space. The ratio of linear momentum of electron $p_e$ to that of photon $p_{Ph}$ , $\frac{p_e}{p_{Ph}}$ is: [Take speed of light $= 3 \times 10^{8}\ \mathrm{ms^{-1}}$ , charge of electron $= -1.6 \times 10^{-19}$ C and mass of electron $= 9 \times 10^{-31}$ kg]
- (A)
  $225$
- (B)
  $275$
- (C)
  $\frac{1}{250}$
- (D)
  $\frac{2}{450}$
4.
NEET 2026
Match List I with List II. List-I: A. $E=h\nu$ , B. Diffraction and Interference, C. $\lambda=h/p$ , D. Compton effect List-II: I. de Broglie wavelength, II. Particle nature of light, III. Wave nature of light, IV. Energy of photon Choose the correct answer from the options given below.
- (A)
  A-IV, B-III, C-II, D-I
- (B)
  A-I, B-IV, C-III, D-II
- (C)
  A-IV, B-I, C-II, D-III
- (D)
  A-IV, B-III, C-I, D-II
5.
NEET 2026
For a metal of work function 6.6 eV, which of the following wavelengths of incident radiation does not give rise to the photoelectric effect? (Take Planck's constant as $6.6\times10^{-34}$ J s)
- (A)
  50 nm
- (B)
  200 nm
- (C)
  100 nm
- (D)
  150 nm
6.
NEET 2024
The graph which shows the variation of $\left(\dfrac{1}{\lambda^2}\right)$ and its kinetic energy, $E$ is (where $\lambda$ is de Broglie wavelength of a free particle):
- (A)
- (B)
- (C)
- (D)
7.
NEET 2024
If $c$ is the velocity of light in free space, the correct statements about photon among the following are: A. The energy of a photon is $E=h\nu$ . B. The velocity of a photon is $c$ . C. The momentum of a photon, $p=\dfrac{h\nu}{c}$ . D. In a photon-electron collision, both total energy and total momentum are conserved. E. Photon possesses positive charge. Choose the correct answer from the options given below:
- (A)
  A, C and D only
- (B)
  A, B, D and E only
- (C)
  A, B, C and D only
- (D)
  A and B only
8.
NEET 2023
The work functions of Caesium (Cs), Potassium (K) and Sodium (Na) are $2.14\ \mathrm{eV}$ , $2.30\ \mathrm{eV}$ and $2.75\ \mathrm{eV}$ respectively. If incident electromagnetic radiation has an incident energy of $2.20\ \mathrm{eV}$ , which of these photosensitive surfaces may emit photoelectrons?
- (A)
  Na only
- (B)
  Cs only
- (C)
  Both Na and K
- (D)
  K only
9.
NEET 2022
When two monochromatic lights of frequency $\nu$ and $\dfrac{\nu}{2}$ are incident on a photoelectric metal, their stopping potentials become $\dfrac{V_s}{2}$ and $V_s$ respectively. The threshold frequency for this metal is:
- (A)
  $\dfrac{3}{2}\nu$
- (B)
  $2\nu$
- (C)
  $3\nu$
- (D)
  $\dfrac{2}{3}\nu$
10.
NEET 2022
The graph which shows the variation of the de Broglie wavelength ( $\lambda$ ) of a particle and its associated momentum ( $p$ ) is:
- (A)
  a curve where $\lambda$ falls steeply and continuously as $p$ increases (a rectangular hyperbola, $\lambda \propto 1/p$ )
- (B)
  a straight line through the origin with $\lambda$ increasing linearly as $p$ increases
- (C)
  a straight line with $\lambda$ decreasing linearly as $p$ increases, crossing the $p$ -axis
- (D)
  a curve where $\lambda$ increases with increasing slope as $p$ increases
11.
NEET 2021
The number of photons per second on an average emitted by the source of monochromatic light of wavelength $600\ \mathrm{nm}$ , when it delivers the power of $3.3\times10^{-3}$ watt will be : ( $h = 6.6\times10^{-34}\ \mathrm{Js}$ )
- (A)
  $10^{17}$
- (B)
  $10^{16}$
- (C)
  $10^{15}$
- (D)
  $10^{18}$
12.
NEET 2021
An electromagnetic wave of wavelength $\lambda$ is incident on a photosensitive surface of negligible work function. If $m$ mass is of photoelectron emitted from the surface has de-Broglie wavelength $\lambda_d$ , then :
- (A)
  $\lambda = \left(\dfrac{2mc}{h}\right)\lambda_d^{2}$
- (B)
  $\lambda = \left(\dfrac{2h}{mc}\right)\lambda_d^{2}$
- (C)
  $\lambda_d = \left(\dfrac{2mc}{h}\right)\lambda^{2}$
- (D)
  $\lambda = \left(\dfrac{2m}{hc}\right)\lambda_d^{2}$
13.
NEET 2020
Light of frequency $1.5$ times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
- (A)
  doubled
- (B)
  four times
- (C)
  one-fourth
- (D)
  zero
14.
NEET 2020
An electron is accelerated from rest through a potential difference of $V$ volt. If the de Broglie wavelength of the electron is $1.227\times10^{-2}$ nm, the potential difference is :
- (A)
  10 V
- (B)
  $10^{2}$ V
- (C)
  $10^{3}$ V
- (D)
  $10^{4}$ V

Answer key

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