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प्रश्न
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उत्तर
Variable resistors consist of a resistance track with connections at both ends and a wiper which moves along the track as you turn the spindle. The track may be made from carbon, cermet (ceramic and metal mixture), or a coil of wire (for low resistances). The track is usually rotary but straight track versions, usually called sliders, are also available.
Variable resistance is a device used to change the resistance and hence the current flowing through a circuit; without changing the voltage.
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संबंधित प्रश्न
Write symbol and state function of following component in an electric circuit : key
Write symbol and state function of following component in an electric circuit :
voltmeter
(a) Complete the circuit given in Fig. by inserting between the terminals A and C. an ammeter.
(b) In the diagram, mark the polarity at the terminals of ammeter and indicate clearly the direction of flow of current in the circuit when the circuit is complete.
(c) Name and state the purpose of Rh in the circuit.
'The resistance of a wire is 1 ohm'. Explain the meaning of this statement.
State three factors on which the resistance of a wire depends. Explain how the resistance depends on the factors stated by you.
There is a positively charged sphere A and negatively charged sphere B, such that they are brought in electrical contact by a copper wire.
Which sphere is at higher potential before electrical contact on the basis of convention?
State the unit of electric potential and define it.
State SI unit of electric charge and define it.
A charge of 8860 C flows through an electric circuit in 2 min and 40 s. Calculate the magnitude of current in a circuit.
