MCQ Questions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter with Answers

Students are advised to practice the NCERT MCQ Questions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter with Answers Pdf free download is available here. MCQ Questions for Class 12 Physics with Answers are prepared as per the Latest Exam Pattern. Students can solve these Dual Nature of Radiation and Matter Class 12 MCQs Questions with Answers and assess their preparation level.

Dual Nature of Radiation and Matter Class 12 MCQs Questions with Answers

Solving the Dual Nature of Radiation and Matter Multiple Choice Questions of Class 12 Physics Chapter 11 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Dual Nature of Radiation and Matter Class 12 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 11 Physics Class 12 and cross-check your answers during preparation.

I. Choose the correct answer

Question 1.
When the light of frequency 2v0 (where v0 is threshold frequency) is incident on a metal plate, the maximum velocity of electrons emitted is v1. When the frequency of the incident radiation is increased to 5v0, the maximum velocity of electrons emitted from the same plate is v2. The ratio of v1 to v2 is:
(a) 1 : 2
(b) 1 : 4
(c) 4 : 1
(d) 2 : 1

Answer

Answer: (a) 1 : 2


Question 2.
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

Answer

Answer: (b) 1.2 × 10-3 nm


Question 3.
A proton, a neutron, an electron and an a-particle have same energy. Then their de-Broglie wavelengths compare as
(a) λp = λn > λe > λa
(b) λα < λp = λn > λe
(c) λe < λp = λn > λa
(d) λe = λp = λn = λa

Answer

Answer: (b) λα < λp = λn > λe


Question 4.
The photoelectric threshold wavelength of silver is 3250 × 10-10 m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength 2536 × 10-10 m is:
(Given h = 4.14 × 10-15 eVs and c = 3 × 108 m s-1)
(a) = 0.6 × 105 m s-1
(b) = 61 × 10³ m s-1
(c) = 0.3 × 106 m s-1
(d) = 6 × 105 m s-1

Answer

Answer: (d) = 6 × 105 m s-1


Question 5.
An electron beam is accelerated by a potential difference V to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If λmin is the smallest possible wavelength of X-ray in the spectrum, the variation of log λmin with log V is correctly represented in:
MCQ Questions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter with Answers 1

Answer

Answer:
MCQ Questions for Class 12 Physics Chapter 11 Dual Nature of Radiation and Matter with Answers 2


Question 6.
Photons with energy 5 eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is
(a) – 1 V
(b) – 3 V
(b) + 3 V
(d) + 4 V

Answer

Answer: (b) – 3 V


Question 7.
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

Answer

Answer: (d) H-1/2


Question 8.
An electron is moving with an initial velocity \(\vec {v}\) = v0\(\hat {j}\) and is in a magnetic field
\(\vec {B}\) = B0\(\hat {j}\). Then its de-Broglie wavelength
(a) remains constant
(b) increases with time
(c) decreases with time
(d) increases and decreases periodically

Answer

Answer: (a) remains constant


Question 9.
An electron (mass m) with an initial velocity \(\vec {v}\) = v0\(\hat {j}\) is in an electric field
\(\vec {E}\) = E0\(\hat {j}\). If λ0 = \(\frac { h }{mv_0}\), its de-Broglie wavelength at time t is given by
(a) λ0
(b) λ0 \(\sqrt{1+\left(\frac{e E_{0} t}{m v_{0}}\right)^{0}}\)
(c) \(\frac{\lambda_{0}}{\sqrt{1+\left(\frac{e E_{0} t^{t}}{m v_{0}}\right)^{2}}}\)
(d) \(\frac{\lambda_{0}}{1+\left(\frac{e E_{0} t}{m v_{0}}\right)^{2}}\)

Answer

Answer: (c) \(\frac{\lambda_{0}}{\sqrt{1+\left(\frac{e E_{0} t^{t}}{m v_{0}}\right)^{2}}}\)


II. Fill in the blanks

Question 1.
……………… is the phenomenon of the emission of electrons from a metal surface when radiation of suitable frequency falls on the metal surface.

Answer

Answer: Photoelectric effect


Question 2.
The phenomenon of emission of electrons from a hot metal surface is called ………………

Answer

Answer: Thermionic emission


Question 3.
The minimum energy required by a free electron to just escape from the metal surface is called ………………

Answer

Answer: Work function


Question 4.
This unit of energy commonly used in atomic and nuclear physics is ………………

Answer

Answer: Electron volt (eV)


Question 5.
The work function (Ø0) depends on the properties of the metal and the ……………… of its surface.

Answer

Answer: Nature


Question 6.
……………… is defined as the energy acquired by an electron when it is accelerated through a potential difference of 1 volt.

Answer

Answer: Electron volt


Question 7.
The energy of the photon is given by ………………

Answer

Answer: E = hv = \(\frac { hc }{λ}\).


Question 8.
The velocity of photon in different media is ………………

Answer

Answer: Different


Question 9.
The rest mass of a photon is ………………

Answer

Answer: Zero


Question 10.
In a photon-particle collision (such as photon-electron collision), the total ……………… and total momentum are conserved.

Answer

Answer: Energy


Question 11.
The maximum kinetic energy of emitted photoelectrons depends on the ……………… of incident radiation and the nature of material.

Answer

Answer: Frequency


Question 12.
The maximum kinetic energy of emitted photoelectrons is independent of ……………… of incident radiation.

Answer

Answer: Intensity


Question 13.
The photoelectric current of emitted photoelectrons depends on the ……………… of incident radiation.

Answer

Answer: Intensity


Question 14.
The photo-electric current of emitted photoelectrons is independent of the ……………… of incident radiation.

Answer

Answer: Frequency


Question 15.
The minimum frequency required to eject an electron from the surface of a metal surface is called ……………… frequency.

Answer

Answer: Threshold


Question 16.
For a frequency v of incident radiation, ……………… than the cut-off frequency v0, no photoelectric emission is possible even if the intensity is large.

Answer

Answer: lower


Question 17.
Photons are electrically ……………… and are not deflected by electric and magnetic fields.

Answer

Answer: Neutral


Question 18.
Davison-Germer experiment verified the ……………… nature of moving electrons.

Answer

Answer: Wave


Question 19.
The expression for de-Broglie wavelength of an electron moving under a potential difference of V volt is ………………

Answer

Answer: λ = \(\frac { 1.227 }{√V}\) nm


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