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प्रश्न
What is emf?
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उत्तर
When no current is drawn from the cell, i.e., 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
Fill in the folloing blank with suitable words:
A current is a flow of ............... .For this to happen there must be a ............... circuit.
Why should the resistance of:
an ammeter be very small?
Draw a circuit diagram to show how two 4 V electric lamps can be lit brightly from two 2 V cells.
Consider the circuit given below:
(a) In which circuit are the lamps dimmest?
(b) In which circuit or circuits are the lamps of equal brightness to the lamps in circuit (i)?
(c) Which circuit gives out the maximum light?
The following circuit diagram shows three resistors 2 Ω, 4 Ω and R Ω connected to a battery of e.m.f 2V and internal resistance 3 Ω. If the main current of 0.25 A flows through the circuit, find:
- the p.d. across the 4 Ω resistors,
- the p.d. across the internal resistance of the cell,
- the p.d. across the R Ω or 2 Ω resistors, and
- the value of R.
Define the following:
Super conductors
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:
The magnitude of Alternating Current (AC):
The value used for practical measurement of Alternating Current is the:
