Explanation:
The transformer does this by linking together two or more electrical circuits using .The two coil windings are not electrically connected but are only .The difference in voltage between the primary and the secondary windings is .Also this induced voltage has the same frequency as the primary winding voltage.The current induced in primary circuit is of same nature as in secondary circuit with differences in amplitude only.A transformer is a static electrical device that transfers electrical energy between two or more circuits through electromagnetic induction.
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A double convex lens of glass of m = 1.5 has radius of curvature of each of its surface is 0.2 m. The power of the lens is
|
(a) + 10 dioptres |
(b) – 10 dioptres |
(c) – 5 dioptres |
(d) +5 dioptres |
The output of a dynamo using a splitting commutator is
|
(a) dc |
(b) ac |
|
(c) Fluctuating dc |
(d) Half-wave rectified voltage |
A coil of self inductance 50 henry is joined to the terminals of a battery of e.m.f. 2 volts through a resistance of 10 ohm and a steady current is flowing through the circuit. If the battery is now disconnected, the time in which the current will decay to 1/e of its steady value is
|
(a) 500 seconds |
(b) 50 seconds |
(c) 5 seconds |
(d) 0.5 seconds |
A capacitor is charged by using a battery which is then disconnected. A dielectric slab is then slipped between the plates, which results in
|
(a) Reduction of charge on the plates and increase of potential difference across the plates |
|
(b) Increase in the potential difference across the plate, reduction in stored energy, but no change in the charge on the plates |
|
(c) Decrease in the potential difference across the plates, reduction in the stored energy, but no change in the charge on the plates |
|
(d) None of the above |
The focal length of the objective of a compound microscope if fo and its distance from the eyepiece is L. The object is placed at a distance u from the objective. For proper working of the instrument:
Average energy stored in a pure inductance L when a current i flows through it, is
|
(a) |
(b) |
(c) |
(d) |
