JEE Questions for Physics Dual Nature Of Radiation And Matter Quiz 17 - MCQExams.com

Assuming photoemission to take place, the factor by which the maximum velocity of the emitted photoelectrons changes when the wavelength of the incident radiation is increased four times is
  • 4
  • 1/4
  • 2
  • 1/2
Work function of a metal is 2.51 eV. Its threshold frequency is
  • 5.9 × 1014 cycles/s
  • 6.5 × 1014 cycles/s
  • 9.4 × 1014 cycles/s
  • 6.08 × 1014 cycles/s
Which one of the following is true in photo electric emission?
  • Photoelectric current is directly proportional to the amplitude of light of a given frequency
  • Photoelectric current is directly proportional to the intensity of light of a given frequency at moderate intensities
  • Above the threshold frequency, the maximum K.E. of photoelectrons is inversely proportional to the frequency of incident light
  • The threshold frequency depends upon the wavelength of incident light
An electromagnetic radiation has an energy of 13.2 keV. Then the radiation belongs to the region of
  • Visible light
  • Ultraviolet
  • Infrared
  • X-ray
As the intensity of incident light increases
  • Photoelectric current increases
  • Photoelectric current decreases
  • Kinetic energy of emitted photoelectrons increases
  • Kinetic energy of emitted photoelectrons decreases
Light of wavelength 5000 Å falls on a sensitive plate with photoelectric work fucntion of 1.9 eV. The kinetic energy of the photoelectron emitted will be
  • 0.58 eV
  • 2.48 eV
  • 1.24 eV
  • 1.16 eV
When light of wavelength 300 nm (nanometer) falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, however light of 600 nm wavelength is sufficient for creating photoemission. What is the ratio of the work functions of the two emitters
  • 1 : 2
  • 2 : 1
  • 4 : 1
  • 1 : 4
The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2> W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hv> W2)
  • I1= I2
  • I12
  • I1>I2
  • I12<2I1
A beam of light of wavelength λ and with illumination L falls on a clean surface of sodium. If N photoelectrons are emitted each with kinetic energy E, then
  • N ∝ L and E ∝ L
  • N ∝ L and E ∝ 1/λ
  • N ∝ λ and E ∝ L
  • N ∝ 1/λ and E ∝ 1/L
The threshold frequency for certain metal is 3.3 × 1014 Hz. If light of frequency 8.2 x 1014 Hz isincident on the metal, the cut-off voltage of the photoelectric current will be
  • 4.9 V
  • 3.0 V
  • 2.0 V
  • 1.0 V
For intensity I of a light of wavelength 5000 Åthe photoelectron saturation current is 0.40 µA and stopping potential is 1.36 V, the work function of metal is
  • 2.47 eV
  • 1.36 eV
  • 1.10 eV
  • 0.43 eV
The work function of aluminum is 4.2 eV. If two photons, each of energy 3.5 eV strike an electron of aluminum, then emission of electrons will be
  • Possible
  • Not possible
  • Data is incomplete
  • Depends upon the density of the surface
In photoelectric effect, the electrons are ejected from metals if the incident light has certain minimum
  • Wavelength
  • Frequency
  • Amplitude
  • Angle of incidence
When photons of energy hv for on an aluminum plate (of work function = E0), photoelectrons of maximum kinetic energy K are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy ofthe ejected photoelectrons will be
  • K
  • K + hv
  • K + E0
  • 2K
The work functions of metals A and B are in the ratio 1: 2. If light of frequencies f and 2f are incident on the surface of A and B respectively, the ratio of the maximum kinetic energies of photo electrons emitted is (f is greater than threshold frequency of A, 2f is greater than threshold frequency of B)
  • 1 : 1
  • 1 : 2
  • 1 : 3
  • 1 : 4
A photo-cell employs photoelectric effect of convert
  • Change in the intensity of illumination into a change in the work function of the photo cathode
  • Change in the frequency of light into a change in the electric current
  • Change in the frequency of light into a change in electric voltage
  • Change in the intensity of illumination into a change in photoelectric current
4 eV is the energy of the incident photon and the work function is 2 eV. What is the stopping potential?
  • 2V
  • 4V
  • 6V
  • 2√2 V
Light of frequency v is incident on a certain photoelectric substance with threshold frequency vo. The work function for the substance is
  • hv
  • hv0
  • h (v – v0)
  • h(v + v0)
The light rays having photons of energy of 1.8 eV are falling on a metal surface having a work function 1.2 eV. What is the stopping potential to be applied to stop the emitting electrons?
  • 3 eV
  • 1.2 eV
  • 0.6 eV
  • 1.4 eV
The photoelectric threshold wavelength for potassium(work function being 2 eV) is
  • 310 nm
  • 620 nm
  • 1200 nm
  • 2100 nm
When a beam of accelerated electrons hits a target, a continuous X-ray spectrum is emitted from the target. Which of the following wavelength is absent in the X-ray spectrum, if the X-ray tube is operating at 40,000 volts?
  • 0.25 Å
  • 0.5 Å
  • 1.5 Å
  • 1.0 Å
For photoelectric emission, tungsten requires light of 2300 Å. If light of 1800 Å wavelength is incident then emission
  • Takes place
  • Doesn't take place
  • May or may not take place
  • Depends on frequency
Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively, successively illuminates a metal of work function 0.5 eV. The ratio of maximum kinetic energy of the emitted electron will be
  • 1 : 5
  • 1 : 4
  • 1 ; 2
  • 1 : 1
Photon of 5.5 eV energy falls on the surface of the metal emitting photoelectrons of maximum kinetic energy 4.0 eV. The stopping voltage required for these electrons are
  • 5.5 V
  • 1.5 V
  • 9.5 V
  • 4.0 V
The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100 W is (taking h =6 ×10–34 J-s)
  • 100
  • 1000
  • 3 × 1020
  • 3 × 1018
A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed 1/2 m away, the number of electrons emitted by photo cathode would
  • Decrease by a factor of 2
  • Increase by a factor of 2
  • Decrease by a factor of 4
  • Increase by a factor of 4
Two identical metal plates show photoelectric effect by a light of wavelength λA falling on plate A and λB on plate B (λA =2λB). The maximum kinetic energy is
  • 2KA = KB
  • KA< KB /2
  • KA =2KB
  • KA> KB /2
The threshold wavelength for photoelectric effect of a metal is 6500 Å. The work function of the metal is approximately
  • 2 eV
  • 1 eV
  • 0.1 eV
  • 3 eV
When ultraviolet rays are incident on metal plate, then photoelectric effect does not occur. It occurs by the incidence of
  • X-rays
  • Radio wave
  • Infrared rays
  • Green house effect
A photosensitive metallic surface has work function hv0. If photons of energy 2hv0 fall on this surface the electrons come out with a maximum velocity of4 × 106 m/s. When the photon energy is increases to5hv0 then maximum velocity of photo electron will be
  • 2 × 106 m/s
  • 2 × 107 m/s
  • 8 × 105 m/s
  • 8 × 106 m/s
Which of the following shows particle nature of light?
  • Refraction
  • Interference
  • Polarization
  • Photoelectric effect
Light of wavelength 1824 Å, incident on the surface of a metal, produces photo-electrons with maximum energy 5.3 eV. When light of wavelength 1216 Å is used, the maximum energy of photoelectrons is 8.7 eV. The work function of the metal surface is
  • 3.5 eV
  • 13.6 eV
  • 6.8 eV
  • 1.5 eV
If the energy of a photon corresponding to a wavelength of 6000 Å is 3.32 × 10–19 J, the photon energy for a wavelength of 4000 Å will be
  • 1.4 eV
  • 4.9 eV
  • 3.1 eV
  • 1.6 eV
The velocity of photon is proportional to (where v is frequency)

  • Physics-Dual Nature of Radiation and Matter-68294.png
  • 2)
    Physics-Dual Nature of Radiation and Matter-68295.png

  • Physics-Dual Nature of Radiation and Matter-68296.png

  • Physics-Dual Nature of Radiation and Matter-68297.png
The ratio of the energy of a photon with λ = 150 nm tothat with λ = 300 nm is
  • 2
  • 1/4
  • 4
  • 1/2
The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV and the stopping potential for a radiation incident on this surface is 5V.the incident radiation lies in
  • Infra-red region
  • Visible region
  • X-ray region
  • Ultraviolet region
If the threshold wavelenght for sodium is 5420 Å, then the work function of sodium is
  • 4.58 eV
  • 2.28 eV
  • 1.14 eV
  • 0.23 eV
The work function of a metal is
  • The energy for the electron to enter into the metal
  • The energy for producing X-ray
  • The energy is required for an electron to come out from metal surface
  • None of the above
The minimum wavelength of photon is 5000 Å, its energy will be
  • 2.5 eV
  • 50 V
  • 5.48 eV
  • 7.48 eV
Which of one is correct?
  • E2= p2c2
  • E2 = p2c
  • E2 = pc2
  • E2 = p2 /c2
The work function for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein\'s equation, the metals which will emit photo electrons for a radiation of wavelength 4100 A is/are
  • None of these
  • A only
  • A and B only
  • All the three metals
A source S1 is producing 1015 photons per second of wavelength 5000 Å. Another source S2 is producing 1.02 × 1015 photons per second of wavelength 5100 Å.Then (power of S2)/(power of S1) is equal to
  • 0.98
  • 1.00
  • 1.02
  • 1.04
When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectron and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2/, the number of emitted electrons and their maximum kinetic energy arerespectively
  • N and 2T
  • 2N and T
  • 2N and 2T
  • N and T
In a photoelectric experiment, if both the intensity and frequency of the incident light are doubled, then thesaturation photoelectric current
  • Remains constant
  • Is halved
  • Is doubled
  • Becomes four times
  • Becomes six times
If 5% of the energy supplied to a bulb is irradiated as visible light, how many quanta are emitted per second by a 100 W lamp (Assume wavelength of visible light as 5.6 × 10–5 cm)
  • 1.4 × 1019
  • 3 × 103
  • 1.4 × 10–19
  • 3 × 104
An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photoelectron is 10 eV, then the value of n is
  • 5
  • 2
  • 3
  • 4
A 200 W sodium street lamp emits yellow light of wavelength 0.6 pm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is
  • 1.5 × 1020
  • 6 × 1018
  • 62 × 1020
  • 3 × 1019
Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The threshold frequency of the material is
  • 4 × 1015 Hz
  • 5 × 1015 Hz
  • 1.6 × 1015 Hz
  • 2.5 × 1015 Hz
An X-ray tube is operated at 50 kV. The minimum wavelength produced is
  • 0.5 Å
  • 0.75 Å
  • 0.25 Å
  • 1 Å
Which of the following wavelengths fall in X-ray region
  • 100000 Å
  • 1000 Å
  • 1 Å
  • 10–2Å
0:0:1


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