Q.1.
If E1, E2 and E3 are the respective kinetic energies of an electron, an alpha particle and a proton each having the same de Brogli wavelength then
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0%
a)E1 > E3 > E2
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50%
b) E2 > E3 > E1
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50%
c)E1 > E2 > E2
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0%
d)E1=E2=E3
Q.2.
A particle of mass 10-31 kg is moving with velocity equal to 105 m/sec. The wavelength of the particle is equal to
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0%
a) 0
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33%
b) 6.6 ×10-8 m
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67%
c)0.66 m
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0%
d)1.5 × 107
Q.3.
An electron has a speed of 100 m/s with an accuracy of 0.005%. The uncertainty in position will be
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33%
a) 0.14 m
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33%
b) 1.4 m
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0%
c)0.014 m
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33%
d)14.0 m
Explanation
Q.4.
A proton when accelerated through a potential difference of V volts has a wavelength λ associated with it. An α-particle in order to have the same λ must be accelerated through a potential difference of
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33%
a) V volt
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67%
b) 4V volt
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0%
c) 2V volt
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0%
d) V/8 volt
Explanation
Q.5.
The momentum of photon ( in kgms-1) of frequency 109 cycles per second is
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0%
a)7.3 ×10-29
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33%
b) 2.2 × 10-33
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67%
c)6.6 ×10-26
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0%
d)3.1
Q.6.
An electron accelerated through a potential difference of V volts has wavelength λ associated with it. Mass of proton is nearly 2000 times that of electron. In order to have the same λ for proton, it must accelerate through a potential difference o
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67%
a) V volts
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0%
b) 2000 V volt
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0%
c)V/20000 volt
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33%
d)√(2000) v volt
Explanation
Q.7.
A tiny particle of mass 10-13 kg moving with a velocity of 10 cm/sec is associated with the wavelength
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0%
a) 6.62 × 10-20 m
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0%
b)6.62 × 10-20 cm
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67%
c)6.62 × 10-34 cm
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33%
d)6.62 × 10-13 m
Q.8.
The momentum of electrons having a wavelength of 100 A.U. is
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20%
a) 6.6 ×10-32 gm ×cm / sec
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40%
b) 6.6 ×10-29 gm ×cm / sec
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40%
c) 6.6 ×10-25 gm ×cm / sec
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0%
d) 6.6 ×10-21 gm ×cm / sec
Explanation
Q.9.
In Bohr's atom the number of de Broglie waves associated with an electron moving in nth permitted orbit is
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0%
a)n
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33%
b) 2n
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67%
c)n/2
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0%
d)n2
Q.10.
A moving particle is associated with a wave packet or group of waves. The group velocity is equal to
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0%
a) velocity of light
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0%
b) velocity of sound
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100%
c)velocity of particle
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0%
d)1/ particle velocity
Q.11.
According to wave mechanics, a material particle is associated with
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33%
a) a single wave
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0%
b) a wave packet
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67%
c)two progressive waves
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0%
d)a ripple
Q.12.
The de Broglie wavelength of an electron in 1.224 Å. The energy of electron is eV is
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0%
a) 1 eV
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0%
b) 10eV
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67%
c) 100eV
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33%
d) 1224eV
Explanation
Q.13.
The de Broglie wave length associated with an electron moving with (1/10)th of the velocity of light is
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0%
a)0.24 ×10-19 m
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0%
b) 0.24 ×10-10 m
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100%
c)1.24 ×10-10 m
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0%
d)0.48 ×10-10 m
Explanation
Q.14.
The uncertainty principle is applicable to
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0%
a) Large system only
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0%
b) small system only
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67%
c)sub atomic particles only
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33%
d)both sub-atomic and large particle
Q.15.
The de-Broglie wavelength of a molecule of thermal energy KT ( K is Boltzmann constant and T is absolute temperature) is
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0%
a)
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33%
b)
-
33%
c)
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33%
d)
Explanation
Q.16.
The de-Broglie wavelength associated with thermal neutron ( t=51°C say) is of the order of the
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0%
a) Distance between the atoms in the crystal
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67%
b) size of the nucleus
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0%
c) Bohr's radius
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33%
d) size of grain
Explanation
Q.17.
An electron, proton and a car all have same wavelength. The one possessing highest velocity is
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67%
a)electron
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0%
b) proton
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0%
c)car
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33%
d)all have same velocity
Q.18.
The de Broglie wavelength of 150 eV electron will be
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0%
a) 1 Å
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33%
b) 12.27 Å
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0%
c)0.5 Å
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67%
d)1.5 Å
Q.19.
In the hydrogen atom an electron is moving in nth orbit. The circumference s of the orbit and the de Broglie wavelength, λ of the moving electron are related by the equation
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33%
a) s=nλ
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0%
b) s=n/λ
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67%
c)s=λ/n
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0%
d)s=1/ nλ
Q.20.
The uncertainty in the location of a particle is equal to its de Broglie wavelength then the uncertainty in its velocity will be
-
25%
a) Its velocity
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17%
b) Half of its velocity
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33%
c) Twice its velocity
-
25%
d) Four times its velocity
Q.21.
What is the de Broglie wave length of an electron accelerated through 40kV?
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0%
a)614 pm
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0%
b) 61.4 pm
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33%
c)6.14 pm
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67%
d)0.614 pm
Q.22.
The de-Broglie wavelength associated with moving electrons is 0.24×10-10 m. The voltage applied between grids to bring it to rest is
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67%
a) 1000 volts
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0%
b) 2597 volts
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0%
c)2597 volts
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33%
d)none of above
Explanation
Q.23.
Matter waves are similar in nature to
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33%
a) X-rays
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0%
b) γ-rays
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0%
c)Cathode rays
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67%
d)none of the above
Q.24.
The propagation constant of the de Broglie waves associated with an electron is
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0%
a) Proportional to its mass
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33%
b) Proportional to its momentum
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33%
c) Proportional to its energy
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33%
d) Inversely proportional to its energy
Q.25.
The wavelength of the matter wave is independent of
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33%
a)mass
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33%
b) velocity
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0%
c)momentum
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33%
d)charge
Q.26.
An electron accelerated by a potential difference of V volt posses a de Broglie wave length λ. If the accelerating potential is increased by a factor of 4, the de-Broglie wavelength of the electron will be
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0%
a) Remains unchaged
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67%
b) Becomes 4 times
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33%
c)Becomes Half
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0%
d)Becomes double
Q.27.
A photon and electron have same wave length then
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0%
a) photon has greater momentum
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67%
b) electron has greater momentum
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0%
c)they have the same momentum
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33%
d)none of the above
Q.28.
The function of the crystal in Davisson and Germer experiment is
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33%
a) To reflect the electron beam
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0%
b) To refract the electron beam
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33%
c) To diffract the electron beam
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33%
d) To focus the electron beam
Q.29.
The interplanar spacing of crystal is 1.225 Å. the maximum order of diffraction of electrons accelerated through a potential difference of 10 kV is
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0%
a) 1
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67%
b) 20
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33%
c)100
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0%
d)1000
Explanation
Q.30.
A particle of mass 1kg is moving with a velocity of 1m/s. The de-broglie wavelength associated with it will be
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33%
a) h
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0%
b) h/2
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33%
c) h/4
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33%
d) 2h