The work function of metal is 1 eV. Light of wavelength 3000 Å is incident on this metal surface. The velocity of emitted photo-electrons will be
(a) 10 m/sec                           (b) 1×103 m/sec
(c) 1×104 m/sec                     (d) 1×106 m/sec

Concept Questions :-

Einstein photo-electric equation
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The work function of a metal is 1.6×10-19 J. When the metal surface is illuminated by the light of wavelength 6400 Å, then the maximum kinetic energy of emitted photo-electrons will be
(Planck's constant = 6.4×10-34 Js
(a) 14×10-19 J                 (b) 2.8×10-19 J 
(c) 1.4×10-19 J                (d) 1.4×10-19 eV

Concept Questions :-

Einstein photo-electric equation
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Ultraviolet radiations of 6.2 eV falls on an aluminium surface (work function 4.2 eV ). The kinetic energy in joules of the fastest electron emitted is approximately

(a) 3.2×10-21              (b) 3.2×10-19
(c) 3.2×10-17              (d) 3.2×10-15

Concept Questions :-

Einstein photo-electric equation
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The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength λ for sodium is 5460 Å, the value of λ for tungsten is

(a) 5893 Å                   (b) 10683 Å
(c) 2791 Å                   (d) 528 Å

Concept Questions :-

Photoelectric effect experiment
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A photon of energy 3.4 eV is incident on a metal having work function 2 eV. The maximum K.E. of photo-electrons is equal to 
(a) 1.4 eV                   (b) 1.7 eV
(c) 5.4 eV                   (d) 6.8 eV

Concept Questions :-

Einstein photo-electric equation
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The photoelectric threshold wavelength for a metal surface is 6600 Å. The work function for this is 
(a) 1.87 V                              (b) 1.87 eV
(c) 18.7 eV                             (d) 0.18 eV

Concept Questions :-

Photoelectric effect experiment
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Photoelectric effect was successfully explained first by
(a) Planck                (b) Hallwash
(c) Hertz                  (d) Einstein

Concept Questions :-

Photoelectric effect experiment
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The spectrum of radiation 1.0×1014 Hz is in the infrared region. The energy of one photon of this in joules will be

(a) 6.62×10-48              (b) 6.62×10-20
(c)  6.623×10-28            (d) 3×6.62×10-28

Concept Questions :-

De-broglie wavelength
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A photo cell is receiving light from a source placed at a distance of 1 m. If the same source is to be placed at a distance of 2 m, then the ejected electron

(a) Moves with one-fourth energy as that of the initial energy
(b) Moves with one-fourth of momentum as that of the initial momentum
(c) Will be half in number
(d) Will be one-fourth in number

Concept Questions :-

Electron emission
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In a photoelectric experiment for 4000 Å incident radiation, the potential difference to stop the ejection is 2 V. If the incident light is changed to 3000 Å, then the potential required to stop the ejection of electrons will be

(a) 2 V                     (b) Less than 2 V
(c) Zero                   (d) Greater than 2 V

Concept Questions :-

Einstein photo-electric equation
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