Q.1
in photoelectric effect, the photoelectric current ..[ EAMCET 85]
  • a) Does not depend on photo frequency, but only on intensity of incident bean
  • b) depends both intensity and frequency of incident beam
  • c) increase when frequency of incident photos increases
  • d) decrease when frequency of incident photons increases
Q.2
The maximum energy of the electrons released in photocell is independent of [ EAMCET]
  • a)frequency of incident light
  • b) intensity of incident light
  • c)nature of cathode surface
  • d)none of these
Q.3
Plank's constant has the dimensions of [ NCERT 1990]
  • a) Force
  • b) Energy
  • c)Linear momentum
  • d)Angular momentum
Q.4
X-rays are used to irradiate sodium and copper surface in two separate experiments and stopping potential determined. The stopping potential is
  • a) Equal in both the cases
  • b) Greater for sodium
  • c)Greater for copper
  • d)Infinite in both the cases
Q.5
The variation of photoelectric current given by the photocell with the intensity of light is given by a graph which is
  • a) A parabola
  • b) A straight line with posittive slope passing through origin
  • c) A straight line with positive slope with intercept on current axis
  • d) A straight line with negative slope
Q.6
The stopping potential as function of frequency of incident radiation is plotted for two different photoelectric surfaces A and B. The graphs show that the work function of A is .. [ PMT 1992]
ch-9_que_no-70_img_no1.png
  • a) Greater than that of B
  • b) smaller than that of B
  • c)same as that of B
  • d)No comparison can be done from the given graphs
Q.7
If the distance of 100 watt lamp is increased from a photocell, the saturation current 'i' in the photocell varies with distance 'd' as [ NCERT 1990]
  • a) i ∝ d2
  • b) i ∝ d
  • c)i ∝ 1/ d
  • d)i ∝ 1/d²
Q.8
The work function for photo-electric effect: [ JIMPER 1998]
  • a) is different for different metals
  • b) is same for all metals
  • c) depends upon the frequency of the incident light
  • d) none of the above
Q.9
When a monochromatic point source of light is at a distance of 0.2m from a photoelectric cell, the cut off voltage and saturation current are respectively 0.6V and 18.0 mA. If the same source is placed 0.6 m away from photocell, the [ IIT 1992]
  • a) The stopping potential will be 0.2V
  • b) The stopping potential will be 0.4V
  • c) The sturation current will be 6.0 mA
  • d) The saturation current will be 0.2 mA
Q.10
Which of the following statement is wrong
  • a) Wave nature of particles is not exhibited in daily life
  • b) de Broglie waves are probability waves
  • c)Wavelength of de-Broglie waves is proportional to the momentum of particle
  • d)de-Broglie waves are associated with charged as well as uncharged particles
Q.11
Matter waves associated with moving material particles are
  • a) Electromagnetic waves
  • b) Imaginary waves
  • c)Mechanical waves
  • d)Probability waves
Q.12
Ultraviolet light of wave length 300 nm and intensity 1.0 watt/m2 fall on the surface of a photosensitive material. If one per cent of the incident photons produce photoelectrons then the number of photoelectrons emitted from an area of 1.0 cm2 of the surface is nearly [ AMU 1995]
  • a) 9.61×1014 per sec
  • b) 4.12 ×1013 per sec
  • c)1.51×1014 per sec
  • d)2.13×1011 per sec
Q.13
When a certain metallic surface is illuminated with monochromatic light of wavelength λ, the stopping potential for photoelectric current is 3VWhen the same surface is illuminated by wavelength 2λ the stopping potential is VThe threshold wavelength for this surface for photoelectric effect is ..[ CPMT 1998]
  • a) 6λ
  • b) 4λ
  • c)λ/4
  • d)8λ
Q.14
the frequency and intensity of the incident beam of light falling on the surface of photoelectric material is increased by a factor of two. this will [ CPMT 1988}
  • a) Increase the maximum kinetic energy of the photoelectrons as well as photoelectric current by a factor of two
  • b) Increase the maximum kinetic energy of photoelectrons and would increase the photoelectric current by a factor of two
  • c) Increase the maximum kinetic energy of photoelectrons by a factor of two and will have no effect on photo electric current
  • d) Increase the photoelectric current by a factor of two but will have no effect on the kinetic energy of emitted electrons
Q.15
The threshold wavelength for photoelectric emission from a material is 5200Å. Photoelectrons will be emitted when this material is illuminated with monochromatic radiation from a [ MPPMT 1999]
  • a) 50 watt infra-red lamp
  • b) 1 watt infrared lamp
  • c)50 watt ultraviolet lamp
  • d)1 watt ultraviolet lamp
Q.16
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.17
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.18
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.19
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.20
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.21
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.22
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.23
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.24
The duration of laser pulse is 10-8 sec. The uncertainty in its energy will be (ΔE.Δt ≥ h)
  • d)1 /(6.6×1026) J
  • a) 6.6 × 10⁻²⁶ J
  • b) 6.6 × 10⁻³⁴ J
  • c)6.6 × 10⁻⁴² J
Q.25
Matter waves
  • a) Are electromagnetic waves
  • b) are transverse waves
  • c)are longitudinal waves
  • d)exhibit diffraction
Q.26
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.27
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.28
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.29
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.30
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
0 h : 0 m : 1 s