- A$\frac{1}{\text{r}}$
- B$\frac{1}{\text{r}^2}$
- C$\text{r}$
- D$\text{r}^2$
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Assertion : The possibility of an electric bulb fusing is higher at the time of switching ON and OFF
Reason : Inductive effects produce a surge at the time of switch ON and OFF
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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. |
A copper disc of radius 0.1 m is rotated about its centre with 10 revolutions per second in a uniform magnetic field of 0.1 Tesla with its plane perpendicular to the field. The e.m.f. induced across the radius of disc is
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(a) |
(b) |
(c) π |
(d) 2π |
The pointer of a dead-beat galvanometer gives a steady deflection because
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(a) Eddy currents are produced in the conducting frame over which the coil is wound |
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(b) Its magnet is very strong |
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(c) Its pointer is very light |
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(d) Its frame is made of abonite |
A thermocouple of resistance 1.6Ω is connected in series with a galvanometer of 8Ω resistance. The thermocouple develops and e.m.f. of 10 μV per degree temperature difference between two junctions. When one junction is kept at 0℃ and the other in a molten metal, the galvanometer reads 8 millivolt. The temperature of molten metal, when e.m.f. varies linearly with temperature difference, will be
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(a) 960℃ |
(b) 1050℃ |
(c) 1275℃ |
(d) 1545℃ |
A charge moves in a circle perpendicular to a magnetic field. The time period of revolution is independent of
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(a) Magnetic field |
(b) Charge |
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(c) Mass of the particle |
(d) Velocity of the particle |
If the distance between the plates of parallel plate capacitor is halved and the dielectric constant of dielectric is doubled, then its capacity will
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(a) Increase by 16 times |
(b) Increase by 4 times |
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(c) Increase by 2 times |
(d) Remain the same |