For a given temperature difference, which of the following pairs will generate maximum thermo e.m.f.
|
(a) Antimony-bismuth |
(b) Silver-gold |
(c) Iron-copper |
(d) Lead-nickel |
(a) Antimony-bismuth
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If energy of K-shell electron is – 40000 eV and If 60000 V potential is applied at coolidge tube then which of the following X-ray will get form
|
(a) Continuous |
|
(b) White X-rays |
|
(c) Continuous and all series of characteristic |
|
(d) None of these |
Hydrogen (H), deuterium (D), singly ionized helium (
and doubly ionized lithium (Li) all have one electron around the nucleus. Consider n =2 to n = 1 transition. The wavelengths of emitted radiations are 
and 
respectively. Then approximately
|
(a) |
(b) 4 |
|
(c) |
(d) |
In a wave, the path difference corresponding to a phase difference of f is
|
(a) |
(b) |
(c) |
(d) |
Magnetic field due to a ring having n turns at a distance x on its axis is proportional to (if r = radius of ring)
|
(a) |
(b) |
(c) |
(d) |
Three resistances 4Ω each of are connected in the form of an equilateral triangle. The effective resistance between two corners is
|
(a) 8 Ω |
(b) 12 Ω |
(c) |
(d) |
