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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.).
संबंधित प्रश्न
Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason?
One coulomb charge is equivalent to the charge contained in:
(a) 2.6 × 1019 electrons
(b) 6.2 × 1019 electrons
(c) 2.65 × 1018 electrons
(d) 6.25 × 1018 electrons
An electric circuit consisting of a 0.5 m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key was set up.
Following graph was plotted between V and I values:
What would be the values of `V/I` rations when the potential difference is 0.8 V, 1.2 V and 1.6 V respectively?
What conclusion do you draw from these values?
What is the resistance of the wire?
In the circuit shown below, the voltmeter reads 10 V.
(a) What is the combined resistance?
(b) What current flows?
(c) What is the p.d. across 2 Ω resistor?
(d) What is the p.d. across 3 Ω resistor?
Consider the circuit given below when A, B and C are three identical light bulbs of constant resistance. 
(a) List the bulbs in order of increasing brightness.
(b) If C burns out, what will be the brightness of A now compared with before?
(c) If B burns out instead, what will be the brightness of A and C compared with before?
Which effect of current is utilised in the working of an electric fuse?
Fill in the blank :
1 mA = ............................. A.
State whether true or false. If false, correct the statement.
Current can produce magnetic field.
