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प्रश्न
Define the following:
Electromotive force
Define the emf of a cell.
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उत्तर
Electromotive force: When no current is drawn from a cell, when the cell is in open circuit, the potential difference between the terminals of the cell is called its electromotive force (or e.m.f.).
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संबंधित प्रश्न
How many microamperes are there in 1 ampere?
A battery and three lamps are connected as shown:
Which of the following statements about the currents at X, Y and Z is correct?
(a) The current at Z is greater than that at Y.
(b) The current at Y is greater than that at Z.
(c) The current at X equals the current at Y.
(d) The current at X equals the current at Z.
V1, V2 and V3 are the p.ds. across the 1Ω, 2Ω and 3Ω resistors in the following diagram, and the current is 5 A.
Which one of the columns (a) to (d) shows the correct values of V1, V2 and V3measured in volts?
`V_1` `V_2` `V_3`
(a) 1.0 2.0 3.0
(b) 5.0 10.0 15.0
(c) 5.0 2.5 1.6
(d) 4.0 4.0 2.0
Draw a circuit diagram showing two electric lamps connected in parallel together with a cell and a switch that works both lamps. Mark an â’¶ on your diagram to show where an ammeter should be placed to measure the current.
Calculate the equivalent resistance between A and B in the adjacent diagram.
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The circuit diagram in fig shows two coils of an insulated copper wire wound on a cardboard tube. G is a center zero galvanometer.
(a) Describe what will happen when th e swi tch K is cl osed for severa l
seconds and then opened again .
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In fig. XY is at right angles to the magnetic field. The direction in which XY should be moved to induce an electron flow in the direction Y to X as indicated by the arrow is:
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Match the items in column-I to the items in column-II:
| Column - I | Column - II |
| (i) electric current | (a) volt |
| (ii) potential difference | (b) ohm meter |
| (iii) specific resistance | (c) watt |
| (iv) Electrical power | (d) joule |
| (v) electrical energy | (e) ampere |
