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Dual Nature of Radiation and Matter · Question 7

JEE Main 2026 (Online) 4th April Morning ShiftMCQMedium📈 Topic in 13% papers+4−1
1

The graph shows variation of stopping potential V0 with the frequency of the incident radiation for three photosensitive metals X1, X2 and X3. Which metal will give out electrons with greater kinetic energy, for the same wavelength of incident radiation? [figure]

  1. X1
  2. X2
  3. X3
  4. All the metals will give out photoelectrons with same kinetic energies.

Answer

(1) X1

Solution

[figure]

Einstein's photoelectric equation: K =eV0=h -h 0

⇒ V0= he( - 0): all three lines have the same slope he; the intercept on the -axis is the threshold frequency 0.

Same wavelength ⇒ same for all three metals (dashed line).

∴ K is largest for the metal with the smallest 0 (smallest work function).

0: X1=1.0 1014 Hz < X2=1.5 1014 Hz < X3=2.0 1014 Hz

∴ X1 emits electrons with the greatest kinetic energy.

Answer: (1)

JEE Main 2026 (Online) 4th April Morning Shift

Keep practising — Dual Nature of Radiation and Matter

2

Match the List-I with List-II Choose the correct answer from the options given below :

  1. A-III, B-IV, C-I, D-II
  2. A-I, B-II, C-III, D-IV
  3. A-IV, B-III, C-I, D-II
  4. A-I, B-IV, C-III, D-II
JEE Main 2026 (Online) 4th April Evening Shift
3

The de Broglie wavelength associated with an electron accelerated through a potential difference V is e and the de Broglie wavelength associated with a proton accelerated through the same potential difference is p. If their corresponding masses are me and mp, respectively, then the ratio of their de Broglie wavelengths ( e p ) is .

  1. mpme
  2. memp
  3. mpme
  4. ( mpme )2
JEE Main 2026 (Online) 4th April Evening Shift
4

For a certain metal, when monochromatic light of wavelength is incident, the stopping potential for photoelectrons is 3V0. When the same metal is illuminated by light of wavelength 2 , then the stopping potential becomes V0. The threshold wavelength for photoelectric emission for the given metal is . The value of is .

  1. 1
  2. 4
  3. 2
  4. 3
JEE Main 2026 (Online) 2nd April Morning Shift
5

The ratio of de Broglie wavelength of a deuteron with kinetic energy E to that of an alpha particle with kinetic energy 2E, is n : 1. The value of n is . (Assume mass of proton = mass of neutron)

JEE Main 2026 (Online) 28th January Morning Shift
6

Number of photons of equal energy emitted per second by a 6 mW laser source operating at 663 nm is . (Given : h = 6.63 10-34 J s and c = 3 108 m/s)

  1. 10 1015
  2. 5 1016
  3. 5 1015
  4. 2 1016
JEE Main 2026 (Online) 28th January Evening Shift
7

When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is 3.2 V. If a second light having wavelength twice of first light is used, the stopping potential drops to 0.7 V. The wavelength of first light is m. (h = 6.63 10-34 J s, e = 1.6 10-19 C, c = 3 108 m/s)

  1. 2.9 10-8
  2. 2.5 10-7
  3. 3.1 10-7
  4. 2.2 10-8
JEE Main 2026 (Online) 24th January Evening Shift
8

The de Broglie wavelength of an oxygen molecule at 27 is x 10-12 m. The value of x is (take Planck's constant = 6.63 10-34 J s, Boltzmann constant = 1.38 10-23 J/K, mass of oxygen molecule = 5.31 10-26 kg)

  1. 24
  2. 30
  3. 20
  4. 26
JEE Main 2026 (Online) 23rd January Morning Shift
9

Light is incident on a metallic plate having work function 110 10-20 J. If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is rad/s. (h = 6.63 10-34 J s)

  1. 1.04 1013
  2. 1.66 1016
  3. 1.66 1015
  4. 1.04 1016
JEE Main 2026 (Online) 22nd January Evening Shift
10

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
JEE Main 2026 (Online) 21st January Morning Shift
11

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

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