Q.1
The energy of photon corresponding to the visible light of a maximum wavelength is approximately [ MPPMT 1985]
  • a)1 eV
  • b) 1.6 eV
  • c)3.2 eV
  • d)7.0 eV
Q.2
If position uncertainty of an electron is 2 Å, the uncertainty in energy will be [ raj. PET 1996]
  • a) 0.1 eV
  • b) 1.0 eV
  • c)9.0 eV
  • d)94.0 eV
Q.3
The period of laser is 10-8 sec. The uncertainty in energy
  • d)zero
  • a) 1.05 × 10⁻²⁶ J
  • b) 1.5 × 10⁻²⁵ J
  • c)6.62 × 10⁻²⁶ J
Q.4
To reduce the de Broglie wave length of an electron from 100pm to 50pm, the required increase in energy will be [ Raj PET 1997]
  • a) 600 eV
  • b) 450 eV
  • c) 300 eV
  • d) 150 eV
Q.5
The ratio of de Broglie wavelength for a proton and an α-particle of same energy is [ raj-PET 1996]
  • a)2:1
  • b) 1:2
  • c)4:1
  • d)1:4
Q.6
If a photon has velocity c and frequency ν, then its wave length is equal to [ CBSE 1996]
  • a) hc/E
  • b) hν/c
  • c)hν/ c²
  • d)hν
Q.7
An electron and α particle are accelerated by potential V. The masses are me and malpha then ratio of their momentums will be [ raj. PET 1997]
  • a) me / malpha
  • b)√(me / malpha)
  • c)√(me / 2malpha)
  • d)√(2me / malpha)
Q.8
A proton and an α particle are accelerated through the same potential difference. The ratio of their de Broglie wavelengths ( λp / λα) is
  • a) 1
  • b) 2
  • c) √8
  • d) 1 / √8
Q.9
If Plank's constant is larger than its present value. The de-Broglie wavelength associated with material particles would have been
  • a)unchanged
  • b) larger
  • c)smaller
  • d)larger for some particles and smaller for others
Q.10
A material particle with a rest mass mo is moving with speed of light c. The de-Broglie wavelength associated is given by
  • a) h/moc
  • b) moc / h
  • c) 0
  • d) ∞
Q.11
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
  • a)E1 > E3 > E2
  • b) E2 > E3 > E1
  • c)E1 > E2 > E2
  • d)E₁=E₂=E₃
Q.12
A particle of mass 10-31 kg is moving with velocity equal to 105 m/sec. The wavelength of the particle is equal to
  • a) 0
  • c)0.66 m
  • d)1.5 × 107
  • b) 6.6 ×10⁻⁸ m
Q.13
An electron has a speed of 100 m/s with an accuracy of 0.005%. The uncertainty in position will be
  • a) 0.14 m
  • b) 1.4 m
  • c)0.014 m
  • d)14.0 m
Q.14
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
  • a) V volt
  • b) 4V volt
  • c) 2V volt
  • d) V/8 volt
Q.15
The momentum of photon ( in kgms-1) of frequency 109 cycles per second is
  • d)3.1
  • a)7.3 ×10⁻²⁹
  • b) 2.2 × 10⁻³³
  • c)6.6 ×10⁻²⁶
Q.16
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
  • a) V volts
  • b) 2000 V volt
  • c)V/20000 volt
  • d)√(2000) v volt
Q.17
A tiny particle of mass 10-13 kg moving with a velocity of 10 cm/sec is associated with the wavelength
  • a) 6.62 × 10⁻²⁰ m
  • b)6.62 × 10⁻²⁰ cm
  • c)6.62 × 10⁻³⁴ cm
  • d)6.62 × 10⁻¹³ m
Q.18
The momentum of electrons having a wavelength of 100 A.U. is
  • a) 6.6 ×10⁻³² gm ×cm / sec
  • b) 6.6 ×10⁻²⁹ gm ×cm / sec
  • c) 6.6 ×10⁻²⁵ gm ×cm / sec
  • d) 6.6 ×10⁻²¹ gm ×cm / sec
Q.19
In Bohr's atom the number of de Broglie waves associated with an electron moving in nth permitted orbit is
  • a)n
  • b) 2n
  • c)n/2
  • d)n2
Q.20
A moving particle is associated with a wave packet or group of waves. The group velocity is equal to
  • a) velocity of light
  • b) velocity of sound
  • c)velocity of particle
  • d)1/ particle velocity
Q.21
According to wave mechanics, a material particle is associated with
  • a) a single wave
  • b) a wave packet
  • c)two progressive waves
  • d)a ripple
Q.22
The de Broglie wavelength of an electron in 1.224 Å. The energy of electron is eV is
  • a) 1 eV
  • b) 10eV
  • c) 100eV
  • d) 1224eV
Q.23
The de Broglie wave length associated with an electron moving with (1/10)th of the velocity of light is
  • a)0.24 ×10⁻¹⁹ m
  • b) 0.24 ×10⁻¹⁰ m
  • c)1.24 ×10⁻¹⁰ m
  • d)0.48 ×10⁻¹⁰ m
Q.24
The uncertainty principle is applicable to
  • a) Large system only
  • b) small system only
  • c)sub atomic particles only
  • d)both sub-atomic and large particle
Q.25
The de-Broglie wavelength of a molecule of thermal energy KT ( K is Boltzmann constant and T is absolute temperature) is
  • a)
    ch-9_qn-123choice_img_no1.png
  • b)
    ch-9_qn-123choice_img_no2.png
  • c)
    ch-9_qn-123choice_img_no3.png
  • d)
    ch-9_qn-123choice_img_no4.png
Q.26
The de-Broglie wavelength associated with thermal neutron ( t=51°C say) is of the order of the
  • a) Distance between the atoms in the crystal
  • b) size of the nucleus
  • c) Bohr's radius
  • d) size of grain
Q.27
An electron, proton and a car all have same wavelength. The one possessing highest velocity is
  • a)electron
  • b) proton
  • c)car
  • d)all have same velocity
Q.28
The de Broglie wavelength of 150 eV electron will be
  • a) 1 Å
  • b) 12.27 Å
  • c)0.5 Å
  • d)1.5 Å
Q.29
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
  • a) s=nλ
  • b) s=n/λ
  • c)s=λ/n
  • d)s=1/ nλ
Q.30
The uncertainty in the location of a particle is equal to its de Broglie wavelength then the uncertainty in its velocity will be
  • a) Its velocity
  • b) Half of its velocity
  • c) Twice its velocity
  • d) Four times its velocity
0 h : 0 m : 1 s