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.
2.
3.
4.
The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength for sodium is 5460 Å, the value of for tungsten is
(1) 5893 Å
(2) 10683 Å
(3) 2791 Å
(4) 528 Å
1. | \(1.4\) eV | 2. | \(1.7\) eV |
3. | \(5.4\) eV | 4. | \(6.8\) eV |
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
Photoelectric effect was successfully explained first by
(1) Planck
(2) Hallwash
(3) Hertz
(4) Einstein
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. |
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
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
If the work function for a certain metal is joule and it is illuminated with light of frequency Hz. The maximum kinetic energy of the photo-electrons would be
(a) (b)
(c) (d)