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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Zener breakdown in a semi-conductor diode occurs when
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(a) Forward current exceeds certain value |
(b) Reverse bias exceeds certain value |
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(c) Forward bias exceeds certain value |
(d) Potential barrier is reduced to zero |
The unit of inductance is
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(a) Volt/ampere |
(b) Joule/ampere |
(c) Volt-sec/ampere |
(d) Volt-ampere/sec |
Consider four circuits shown in the figure below. In which circuit power dissipated is greatest (Neglect the internal resistance of the power supply)
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(a)
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(b)
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(c)
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(d)
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A spherical drop of capacitance 1 mF is broken into eight drops of equal radius. Then, the capacitance of each small drop is ......
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(a) |
(b) 8μF |
(c) |
(d) |
Water of volume 2 litre in a container is heated with a coil of 1 kW at 27 oC. The lid of the container is open and energy dissipates at rate of 160 J/s. In how much time temperature will rise from 27oC to 77oC [Given specific heat of water is 4.2 kJ/kg]
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(a) 8 min 20 s |
(b) 6 min 2 s |
(c) 7 min |
(d) 14 min |
Assertion : The comet do not obey Kepler's laws of planetary motion
Reason : The comet do not have elliptical orbit
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
An electron moving towards the east enters a magnetic field directed towards the north. The force on the electron will be directed
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(a) Vertically upward |
(b) Vertically downward |
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(c) Towards the west |
(d) Towards the south |
