Two different metals are joined end to end. One end is kept at constant temperature and the other end is heated to a very high temperature. The graph depicting the thermo e.m.f. is
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(a)
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(b)
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(c)
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(d)
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(d)
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The ratio of de-Broglie wavelengths of molecules of hydrogen and helium which are at temperature 27oC and 127oC respectively is
|
(a) |
(b) |
(c) |
(d) 1 |
When objects at different distances are seen by the eye, which of the following remains constant
|
(a) The focal length of the eye lens |
(b) The object distance from the eye lens |
|
(c) The radii of curvature of the eye lens |
(d) The image distance from the eye lens |
A thin lens made of glass of refractive index m = 1.5 has a focal length equal to 12 cm in air. It is now immersed in water 
Its new focal length is
|
(a) 48 cm |
(b) 36 cm |
(c) 24 cm |
(d) 12 cm |
During mean life of a radioactive element, the fraction that disintegrates is
|
(a) e |
(b) |
(c) |
(d) |
The first member of the Paschen series in hydrogen spectrum is of wavelength 18,800 Å. The short wavelengths limit of Paschen series is
|
(a) 1215 Å |
(b) 6560 Å |
(c) 8225 Å |
(d) 12850 Å |
In a triode valve the amplification factor is 20 and mutual conductance is 10–3 mho. The plate resistance is
|
(a) 2 × 103 W |
(b) 4 × 103 W |
(c) 2 ×104 W |
(d) 2 ×104 W |
Resistance of a voltameter is 2Ω, it is connected in series to a battery of 10 V through a resistance of 3Ω. In a certain time mass deposited on cathode is 1 gm. Now the voltameter and the 3Ω resistance are connected in parallel with the battery. Increase in the deposited mass on cathode in the same time will be
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(a) 0 |
(b) 1.5 gm |
(c) 2.5 gm |
(d) 2 gm |
