# Dual Nature of Radiation and Matter MCQ Class 12 Physics

Please refer to Chapter 11 Dual Nature of Radiation and Matter MCQ Class 12 Physics with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Physics. Students should refer to MCQ Questions for Class 12 Physics with Answers to score more marks in Grade 12 Physics exams. Students should read the chapter Dual Nature of Radiation and Matter and then attempt the following objective questions.

## MCQ Questions Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter

The Dual Nature of Radiation and Matter MCQ Class 12 Physics provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. Protons and alpha particles have the same de-Broglie wavelength. What is same for both of them ?
(a) Energy
(b) Time period
(c) Frequency
(d) Momentum

D

Question. Which of the following when falls on a metal will emit photoelectrons ?
(d) Microwaves

A

Question. Photons are deflected by
(a) electric field only
(b) magnetic field only
(c) electromagnetic field
(d) None of these

D

Question. Which of the following metals is not sensitive to visible light?
(a) Caesium
(b) Sodium
(c) Rubidium

D

Question. The ratio of specific charge of an alpha particle to the proton is:
(a) 1 : 2
(b) 2 : 1
(c) 4 : 1
(d) 1 : 4

A

Question. X-rays are:
(a) deflected by an electric field
(b) deflected by a magnetic field
(c) deflected by both electric and magnetic fields
(d) not deflected by electric and magnetic fields

D

Question. Electrically, photons are
(a) positively charged
(b) negatively charged
(c) neutral
(d) strongly charged, may be positive or negative

C

Question. The theory of quantisation of electric charge was given by
(a) William Crookes
(b) J. J. Thomson
(c) R.A. Millikan
(d) Wilhelm Hallwachs

C

Question. Which theory of light is wave theory or particle theory?
(a) Dynamic physics
(b) Static physics
(c) Quantum mechanics
(d) de – Broglie hypothesis

C

Question. It is essential to consider light as a stream of photons to explain
(a) diffraction of light
(b) refraction of light
(c) photoelectric effect
(d) reflection of light

C

Question. An electron, an alpha-particle, and a proton have the same kinetic energy. Which of these particles has the shortest de Broglie wavelength?
(a) electron
(b) proton
(c) alpha-particle
(d) Cannot say

C

Question. The Davisson-Germer experiment demonstrated the
(a) particle nature of electron
(b) wave nature of electron
(c) wave nature of photon
(d) particle nature of

A

Question. The electrons ejected from metals due to effect of light are called
(a) primary electrons
(b) thermions
(c) secondary electrons
(d) photoelectrons

D

Question. A photoelectric cell converts
(a) light energy into heat energy
(b) light energy to sound energy
(c) light energy into electric energy
(d) electric energy into light energy

C

Question. Which of the following radiations cannot eject photo electrons?
(a) ultraviolet
(b) infrared
(c) visible
(d) X-rays

B

Question. Which phenomenon best supports the theory that matter has a wave nature?
(a) Electron momentum
(b) Electron diffraction
(c) Photon momentum
(d) Photon diffraction

B

Question. Two metals A and B have work function 2eV and 4 eV respectively .which metal has a lower threshold wavelength for the photoelectric effect?
(a) A.
(b) B.
(c) Same for both.
(d) Cannot say.

B

Question. Which of the following shows particle nature of light?
(a) Photoelectric effect
(b) Refraction
(c) Interference
(d) Polarisation

A

Question. Cathode ray consists of
(a) photons
(b) electrons
(c) protons
(d) α-particles

B

Question. The maximum energy of electrons released in a photocell is independent of
(a) the frequency of the incident light
(b) the intensity of the incident light
(c) the nature of the cathode
(d) All of the above

C

Question. In photoelectric effect what determines the maximum velocity of the electron reacting with the collector?
(a) Frequency of incident radiation alone
(b) The potential difference between the emitter and the collector
(c) The work function of metal
(d) All of these

D

Question. Which of the following when falls on a metal will emit photoelectrons ?
(d) Microwaves

A

Question. Consider the following statements:
I. According to de Broglie hypothesis, particles have wave-like characteristics.
II. When an electron and a proton have the same de Broglie wavelength, they will have equal momentum.
Which of the above statements is/are correct?
(a) I only
(b) II only
(c) both I and II
(d) neither I nor II

C

Question. For a given kinetic energy which of the following has smallest de Broglie wavelength?
(a) Electron
(b) Proton
(c) Deutron
(d) a-particle

D

Question. A particle is dropped from a height H. The de-Broglie wavelength of the particle as a function of height is proportional to
(a) H
(b) H1/2
(c) H°
(d) H-1/2

D

Question. A photoelectric cell is a device which
(a) converts light into electricity
(b) converts electricity into light
(c) stores light
(d) stores electricity

A

Question. A Proton and an a-particle have the same de Broglie wavelength. What is same for both of them?
(a) Mass
(b) Energy
(c) Frequency
(d) Momentum

D

Question. Which of the following devices is sometimes called an electric eye?
(a) LED
(b) Photocell
(c) Integrated chip (IC)
(d) Solar cell

B

Question. Kinetic energy of emitted electrons depends upon :
(a) frequency
(b) intensity
(c) nature of atmosphere surrounding the electrons
(d) none of these

A

Question. The stopping potential is directly related to
(a) the work function of the metal
(c) the saturation current for the given frequency
(d) the kinetic energy gained by the photoelectrons

D

Question. Who established that electric charge is quantised?
(a) J.J. Thomson
(b) William Crookes
(c) R.A. Millikan
(d) Wilhelm Rontgen

C

Question. The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nucleus with 1 MeV energy is nearly
(a) 1.2 nm
(b) 1.2 × 10-3 nm
(c) 1.2 × 10-6 nm
(d) 1.2 × 101 nm

B

Question. Photoelectric emission occurs only when the incident light has more than a certain minimum
(a) power
(b) wavelength
(c) intensity
(d) frequency

D

Question. The charge of a photo electron is :
(a) 9.1 x 10-31 C
(b) 9.1 x 10-27 C
(c) 9.1 x 10-24 C
(d) none of these

D

Question. The phenomenon of photoelectric emission was discovered in 1887 by
(a) Albert Einstein
(b) Heinrich Hertz
(c) Wilhelm Hallwachs
(d) Philipp Lenard

B

Question. Calculate the de Broglie wavelength associated with the electron which has a kinetic energy of 5 eV.
(a) 5.47 Å
(b) 2.7 Å
(c) 5.9 Å
(d) None of the above

A

Question. In photoelectric effect, stopping potential depends on
(a) frequency of incident light
(b) nature of the emitter material
(c) intensity of incident light
(d) both (a) and (b)

D

Question. Cathode rays were discovered by :
(a) Maxwell Clerk James
(b) Heinrich Hertz
(c) William Crookes
(d) J. J. Thomson

C

Question. β-rays are deflected in:
(a) gravitational field
(b) only in magnetic field
(c) only in electric field
(d) both in magnetic and electric fields

D

Question. Kirchhoffe’s second law of conservation of :-
(a) charge
(b) energy
(c) momentum
(d) angular momentum

B

Question. The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nucleus with 1 MeV energy is nearly
(a) 1.2 nm
(b) 1.2 × 10–3 nm
(c) 1.2 × 10–6 nm
(d) 1.2 × 101 nm

B

Question. A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of 3 × 106 ms –1. The velocity of the particle is (mass of electron = 9.1 × 10–31 kg)
(a) 2.7 × 10–18 ms–1
(b) 9 × 10–2 ms–1
(c) 3 × 10–31 ms–1
(d) 2.7 × 10–21 ms–1

A

Question. The photoelectric work function for a metal surface is 4.125 eV. The cut-off wavelength for this surface is
(a) 4125 Å
(b) 3000 Å
(c) 6000 Å
(d) 2062 Å

B

Question. The ratio of de-Broglie wavelengths of proton and a -particle having same kinetic energy is
(a) √2 : 1
(b) 2 √2 : 1
(c) 2 : 1
(d) 4 : 1

C

Question. X-rays are produced in X-ray tube operating at a given accelerating voltage. The wavelength of the continuous X-rays has values from
(a) 0 to ∝
(b) λmin to ∝, where λmin > 0
(c) 0 to λmax, where λmax < ¥
(d) λmin to λmax, where 0 < λmin < λmax < ∝

B

Question. The energy of a photon of green light of wavelength 5000Å is
(a) 3.459 × 10–19 joule
(b) 3.973 × 10–19 joule
(c) 4.132 × 10–19 joule
(d) 8453 × 10–19 joule

B

Question. As intensity of incident light increases
(a) photoelectric current increase
(b) K.E. of emitted photoelectron increases
(c) photoelectric current decreases
(d) K.E. of emitted photoelectrons decreases

A

Question. White X-rays are called white due to the fact that
(a) they are electromagnetic radiations having nature same as that of white light.
(b) they are produced most abundantly in X ray tubes.
(c) they have a continuous wavelength range.
(d) they can be converted to visible light using coated screens and photographic plates are affected by them just like light.

C

Question. Which of the following figures represent the variation of particle momentum and the associated de-Broglie wavelength?

D

Question. Consider a beam of electrons (each electron with energy E0) incident on a metal surface kept in an evacuated chamber. Then
(a) no electrons will be emitted as only photons can emit electrons.
(b) electrons can be emitted but all with an energy, E0.
(c) electrons can be emitted with any energy, with a maximum of E0 – φ (φ is the work function).
(d) electrons can be emitted with any energy, with a maximum of E0.