Q.1
Figure shows graph of kinetic energy of electrons emitted verses ν for a material exhibiting photoelectric effect. The work function of the material is ..
ch-9_que_no-79_img_no1.png
  • a) 1eV
  • b) 1.5eV
  • c)2eV
  • d)3eV
Q.2
If in a photoelectric experiment, the wavelength of incident radiation is reduced from 6000Å to 4000Å, then [ MPPMT 1999]
  • a) Stopping potential will decrease
  • b) Stopping potential will increase
  • c) Kinetic energy of emitted electrons will decrease
  • d) The value of work-function will decrease
Q.3
the maximum velocity of an electron emitted by light of wavelength λ incident on the surface of metal of workfunction Φ is [ h=plank constant, m=mass of electron, and c=speed of light] [ MPPMT 1998]
  • a)
    ch-9_qn-81choice_img_no1.png
  • b)
    ch-9_qn-81choice_img_no2.png
  • c)
    ch-9_qn-81choice_img_no3.png
  • d)
    ch-9_qn-81choice_img_no4.png
Q.4
Maximum kinetic energy E of photo-electron varies with the frequency (ν) of the incident radiation as one of the following graphs:[ MPPMT 1994]
  • a)
    ch-9_qn-82choice_img_no1.png
  • b)
    ch-9_qn-82choice_img_no2.png
  • c)
    ch-9_qn-82choice_img_no3.png
  • d)
    ch-9_qn-82choice_img_no4.png
Q.5
A gold leaf electroscope is negatively charged and the leaves are observed to diverged by a certain amount. A beam of X-ray is allowed to fall upon the electroscope for a short period. The effect is as follows
  • a)The leaves will diverge further
  • b) There will be no chnage in the divergence of leaves
  • c) The leaves will collapse
  • d)The gold leaves will melt
Q.6
According to Einstein's interpretation of the photoelectric effect, the maximum K.E. of photoelectrons depends on ( hν -W) where ν is the frequency of incident radiation and W is the work function. For three different metals graph plotted between maximum K/E. and the frequency of incident radiations. The three graphs obtained:
  • a) Have different slopes but a constant intercept on y-axis
  • b) Are all parallel to y-axis but at different heights
  • c) same slope but different intercept on y-axis
  • d) none of these
Q.7
According to the modern theory for nature of light, the light has..[ MPPMT 1998]
  • a)Wave nature only
  • b) Particle nature only
  • c)Both wave and particle ( dual) nature
  • d)neither particle nature nor wave nature
Q.8
The energy of photon is 10eV. The momentum of a photon is
  • a) 5.33×10-25 kg×m /s
  • b) 5.33×10-27 kg×m /s
  • c)5.33×10-29 kg×m /s
  • d)5.33×10-23 kg×m /s
Q.9
When the light of wavelength 2537Å is made incident over the surface of copper slab, the stopping voltage 0.24 volt obtained. The threshold frequency for copper will be .. [ Raj.PMT 1996]
  • a) 1.124×1015 Hz
  • b) 1.414×1014 Hz
  • c)2.248×1015 Hz
  • d)None of the above
Q.10
Given h=6.6×10-34 joules×sec. the momentum of each photon in a given radiation is 3.3×10-29 kg×metre / sec .. [ CBSE 1990]
  • a) 3×10-2 hz
  • b) 6×1010 hz
  • c) 7.5×1012 hz
  • d) 1.5×1013hz
Q.11
According to de Broglie, the waves are associated with
  • a)Moving charged particles only
  • b) Moving neutral particles only
  • c)Electrons only
  • d)All moving particles
Q.12
The duration of laser pulse is 10-8 sec. The uncertainty in its energy will be (ΔE.Δt ≥ h)
  • a) 6.6 × 10-26 J
  • b) 6.6 × 10-34 J
  • c)6.6 × 10-42 J
  • d)1 /(6.6×1026) J
Q.13
Matter waves
  • a) Are electromagnetic waves
  • b) are transverse waves
  • c)are longitudinal waves
  • d)exhibit diffraction
Q.14
If the kinetic energy of moving particle is E, then de Broglie wavelength is
  • a)
    ch-9_qn-92choice_img_no1.png
  • b)
    ch-9_qn-92choice_img_no2.png
  • c)
    ch-9_qn-92choice_img_no3.png
  • d)
    ch-9_qn-92choice_img_no4.png
Q.15
de Broglie wave length associated with a moving particle of mass m, velocity v is given by ( c=speed of light)
  • a)λ hmv
    ch-9_qn-93choice_img_no4.png
  • b) λ=h/mv
  • c)λ=v/mh
  • d)
Q.16
Neglecting variation of mass with energy the wavelength associated with an electron having a kinetic energy E is proportional to
  • a) √E
  • b) E
  • c)E-1/2
  • d)E-2
Q.17
Of the following, moving with the same velocity, the one which has largest wavelength λ is
  • a) an electron
  • b) a proton
  • c)an alpha particle
  • d)all have same de Broglie wave length
Q.18
The energy of photon is 10eV. The momentum of a photon is
  • a) 5.33 × 10-25 kg×m/s
  • b) 5.33 × 10-27 kg×m/s
  • c) 5.33 × 10-29 kg×m/s
  • d) 5.33 × 10-23 kg×m/s
Q.19
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.20
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.21
The period of laser is 10-8 sec. The uncertainty in energy
  • a) 1.05 × 10-26 J
  • b) 1.5 × 10-25 J
  • c)6.62 × 10-26 J
  • d)zero
Q.22
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.23
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.24
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.25
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.26
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.27
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.28
Given Plank's constant h=6.6×10-34 J-sec. The momentum of each photon in a given radiation is 3.3 ×10-29 kg-m/sec. The wave-length of radiation is
  • a) 3 × 10-3 m
  • b) 6 × 10-10 m
  • c)7.5 × 10-2 m
  • d)2 × 10-5 m
Q.29
When electrons are accelerated through potential difference of V volts, the de Broglie wavelength associated is given by
  • a) √(150/V) Å
  • b) √(150/V) m
  • c)(150/ √V) Å
  • d)(√150/V) Å
Q.30
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) ∞
0 h : 0 m : 1 s