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
1. 3.2×10-21             

2. 3.2×10-19

3. 3.2×10-17             

4. 3.2×10-15

Subtopic:  Einstein's Photoelectric 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

(1) 5893 Å                   

(2) 10683 Å

(3) 2791 Å                   

(4) 528 Å

Subtopic:  Photoelectric Effect: Experiment |
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A photon of energy \(3.4\) eV is incident on a metal having a work function of \(2\) eV. The maximum K.E of photo-electrons is equal to:
1. \(1.4\) eV 2. \(1.7\) eV
3. \(5.4\) eV 4. \(6.8\) eV
Subtopic:  Einstein's Photoelectric Equation |
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The photoelectric threshold wavelength for a metal surface is 6600 Å. The work function for this is 
(1) 1.87 V                             

(2) 1.87 eV

(3) 18.7 eV                             

(4) 0.18 eV

Subtopic:  Photoelectric Effect: Experiment |
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Photoelectric effect was successfully explained first by
(1) Planck               

(2) Hallwash

(3) Hertz                 

(4) Einstein

Subtopic:  Photoelectric Effect: Experiment |
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A photocell is receiving light from a source placed at a distance of \(1\) m. If the same source is placed at a distance of \(2\) m, then the ejected electron:
1. moves with one-fourth of energy as that of the initial energy.
2. moves with one-fourth of momentum as that of the initial momentum.
3. will be half in number.
4. will be one-fourth in number.
Subtopic:  Electron Emission |
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In a photoelectric experiment for \(4000~\mathring{A}\) incident radiation, the potential difference to stop the ejection is \(2~\text{V}\). If the incident light is changed to \(3000~\mathring{A}\), then the potential required to stop the ejection of electrons will be:
1. \(2~\text{V}\)
2. Less than \(2~\text{V}\)
3. Zero
4. Greater than \(2~\text{V}\)
Subtopic:  Einstein's Photoelectric Equation |
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Light of wavelength \(4000~\mathrm{\mathring{A}}\) is incident on a sodium surface for which the threshold wavelength of photoelectrons is \(5420~\mathrm{\mathring{A}}\). The work function of sodium is:
1. \(4.58\) eV
2. \(2.29\) eV
3. \(1.14\) eV
4. \(0.57\) eV

Subtopic:  Photoelectric Effect: Experiment |
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Photocell is a device to: 

(1) Store photons

(2) Measure light intensity

(3) Convert photon energy into mechanical energy

(4) Store electrical energy for replacing storage batteries

Subtopic:  Electron Emission |
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If the work function for a certain metal is 3.2×10-19 joule and it is illuminated with light of frequency 8×1014 Hz. The maximum kinetic energy of the photo-electrons would be h=6.63×10-34 Js

(a) 2.1×10-19 J              (b) 8.5×10-19 J 
(c) 5.3×10-19 J              (d) 3.2×10-19 J

Subtopic:  Einstein's Photoelectric Equation |
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