Two ends of a conductor are at different temperatures the electromotive force generated between two ends is
|
(a) Seebeck electro motive force (e.m.f.) |
(b) Peltier electro motive force (e.m.f.) |
|
(c) Thomson electro motive force (e.m.f.) |
(d) None of these |
(c) Thomson electro motive force (e.m.f.)
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An electron is moving with a speed of 
perpendicular to a uniform magnetic field of intensity B. Suddenly intensity of the magnetic field is reduced to B/2. The radius of the path becomes from the original value of r
|
(a) No change |
(b) Reduces to r / 2 |
(c) Increases to 2r |
(d) Stops moving |
In a transistor configuration b-parameter is
|
(a) |
(b) |
(c) 
|
(d) 
|
In Young’s double-slit experiment, an interference pattern is obtained on a screen by a light of wavelength 6000 Å, coming from the coherent sources S1 and S2. At certain point P on the screen third dark fringe is formed. Then the path difference S1P – S2P in microns is
|
(a) 0.75 |
(b) 1.5 |
(c) 3.0 |
(d) 4.5 |
1 g of hydrogen is converted into 0.993 g of helium in a thermonuclear reaction. The energy released is
|
(a) 63 |
(b) 63 |
(c) 63 |
(d) 63 |
In the electric field of a point charge q, a certain charge is carried from point A to B, C, D and E. Then the work done
|
(a) Is least along the path AB |
(b) Is least along the path AD |
|
(c) Is zero along all the paths AB, AC, AD and AE |
(d) Is least along AE |
For copper-iron (Cu-Fe) couple, the thermo e.m.f. (temperature of cold junction = 0℃) is given by E = (14θ – 0.02
)μV. The neutral temperature will be
|
(a) 350 ℃ |
(b) 350 K |
(c) 560℃ |
(d) 560 K |
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 |
