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Mere Teacher · Previous Year Questions
JEE Main Physics · Dual Nature of Matter & Radiation · Set 6 (Q151-180)
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151.
A radiation of 3.8eV falls on a metal surface to produce photo electrons. These electrons are made to enter a magnetic field of 2×10−4T. If the radius of the largest circular path followed by these electrons is 30mm, then work function of the metal is (Mass of electron me=9×10−31kg )
(1)0.9eV
(2)1.0eV
(3)0.6eV
(4)1.2eV
152.
An electron of mass m, when accelerated through a potential difference V, has de Broglie wavelength λ. The de Broglie wavelength associated with a proton of mass M accelerated through the same potential difference, will be
(1)λmM
(2)λMm
(3)λmM
(4)λMm
153.
If we consider electrons and photons of same wavelength, then they will have same
(1)momentum
(2)angular momentum
(3)energy
(4)velocity.
154.
A particle is dropped from a height ' H. The de Broglie wavelength of the particle depends on height as
(1)H
(2)H−1/2
(3)H0
(4)H1/2
155.
Which of the following particle has the shortest de Broglie wavelength?
(1)Proton
(2)Electron
(3)α-particle
(4)X-rays
156.
The maximum velocity of the photoelectron emitted by the metal surface is ' V. Charge and mass of the photoelectron is denoted by ' e ' and ' m ' respectively. The stopping potential in volt is
(1)2(m/e)V2
(2)2(e/m)V2
(3)(e/m)V2
(4)(m/e)V2
157.
The ratio of wavelengths of proton and deuteron accelerated by potential Vp and Vd is 1:2. Then, the ratio of Vp to Vd will be
(1)1 : 1
(2)2:1
(3)2 : 1
(4)4 : 1
158.
Proton (P) and electron (e) will have same de-Broglie wavelength when the ratio of their momentum is (assume, mp = 1849 me)
(1)1 : 1
(2)1: 1849
(3)1 : 43
(4)43 : 1
159.
Light of wavelength 500 nm is incident on a metal with work function 2.28 eV The de Broglie wavelength of the emitted electron is
(1)≥2.8×10−9m
(2)≤2.8×10−12m
(3)<2.8×10−10m
(4)<2.8×10−9m.
160.
The value of Plank's constant, if the slope of the graph of stopping potential vs frequency of incident light is 4×10−15Vs is (given charge of an electron =1.6×10−19C )
(1)6.0×10−34Js
(2)6.2×10−34Js
(3)6.4×10−34Js
(4)6.6×10−34Js
161.
If the wavelength of a photon is 4000Å, then its energy will be
(1)4.95×10−19J
(2)5.95×10−19J
(3)3.95×0−19J
(4)6.95×10−19J
162.
Consider two black bodies A and B having equal surface areas. On the surface of A, ' n ' photons of frequency ' f ' are incident perpendicularly in a time ' t '. On the surface of B, ' 2n ' photons of frequency ' 3f ' are incident perpendicularly in a time ' 4t '. The ratio of average intensity of radiation on surface A to that on surface B is
(1)2:3
(2)3:2
(3)1:12
(4)1:24
163.
Let K1 and K2 be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength λ1and λ2, respectively are incident on a metallic surface. If λ1= 3λ2 then:
(1)K1>3K2
(2)K1<3K2
(3)K1=3K2
(4)K2=3K1
164.
An electron with (rest mass m0) moves with a speed of 0.8 c. Its mass when it moves with this speed is
(1)m0
(2)m06
(3)35m0
(4)53m0
165.
A beam of electron passes undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons move
(1)in a circular orbit
(2)along a parabolic path
(3)along a straight line
(4)in an elliptical orbit
166.
In a photo‐emissive cell, with exciting wavelength λ, the fastest electron has speed ν. If the exciting wavelength is changedto 43λ’the speed of the fastest emitted electron will be
(1)less than v(4/3)21
(2)v(4/3)1/2
(3)v(3/4)1/2
(4)greater than v(4/3)1/2
167.
According to de-Broglie hypothesis, the wavelength associated with moving electron of mass m is λe. Using mass energy relation and Planck's quantum theory, the wavelength associated with photon is λp. If the energy (E) of electron and photon is same then relation between λe and λp is
(1)λp∝λe
(2)λp∝λe2
(3)λp∝λe
(4)λp∝λe1
168.
The threshold frequency for photoelectric effect on sodium corresponds to a wavelength of 5000 Å. Its work function is
(1)4×10−19J
(2)1J
(3)2×10−19J
(4)3×10−19J
169.
Given below are two statements: Statement I: Davisson-Germer experiment establishes the wave nature of electrons. Statement II: If electrons have wave nature, they can interfere and show diffraction. In the light of the above statements choose the correct answer from the options given below:-
(1)Both Statement I and Statement II are true
(2)Both Statement I and Statement II are false
(3)Statement I is true but Statement n is false
(4)Statement I is false but Statement II is true
170.
When the light of frequency 2ν0 (where ν0 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 5ν0, the maximum velocity of electrons emitted from the same plate is v2. The ratio of v1to v2 is
(1)1:2
(2)1:4
(3)4:1
(4)2:1
171.
A radio transmitter operates at a frequency 880 kHz and a power of 10 kW. The number of photons emitted per second is
(1)1.72×1031
(2)1.327×1025
(3)1.327×1037
(4)1.327×1045
172.
Light is incident on a metallic plate having work function 110×10−20J. If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is ____rad/s.(h=6.63×10−34J.s).
(1)1.04×1013
(2)1.04×1016
(3)1.66×1016
(4)1.66×1015
173.
If an electron and a proton have the same de-Broglie wavelength, then the kinetic energy of the electron is
(1)more than that of a proton
(2)equal to that of a proton
(3)zero
(4)less than that of a proton.
174.
According to Einstein's photoelectric equation, the graph of K.E. of the photoelectron emitted from the metal versus the frequency of the incident radiation gives a straight line graph, whose slope
(1)depends on the intensity of the incident radiation
(2)depends on the nature of the metal and also on the intensity of incident radiation
(3)is same for all metals and independent of the intensity of the incident radiation
(4)depends on the nature of the metal.
175.
A 60W source emits monochromatic light of wavelength 662.5nm. The number of photons emitted per second is
(1)5×1017
(2)2×1020
(3)5×1026
(4)2×1029
176.
A photoelectric surface is illuminated successively by monochromatic light of wavelength λ and λ/2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface is,
(1)2λhc
(2)λhc
(3)3λhc
(4)λ3hc
177.
Both an electron and a photon have same de-Broglie wavelength of 1.2Å. The ratio of their energies is nearly
(1)1:100
(2)1:10
(3)1:1000
(4)1:1
178.
An electron is accelerated from rest through a potential difference of V volt. If the de-Broglie wavelength of the electron is 1.227×10−2nm, the potential difference is [NEET 2020]
(1)102V
(2)103V
(3)104V
(4)10 V
179.
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=6.63×10−34J.s,e=1.6×10−19C,c=3×108m/s )
(1)2.5×10−7
(2)2.2×10−8
(3)3.1×10−7
(4)2.9×10−8
180.
A particle having electric charge 3×10−19C and mass 6×10−27kg is accelerated by applying an electric potential of 1.21 V. Wavelength of the matter wave associated with the particle is α×10−12m. The value of α is ____ (Take Planck's constant =6.6×10−34J.s )
