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प्रश्न
State the effect of rise in temperature on the resistance of semi-conductors.
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उत्तर
In the case of semi-conductors like carbon, silicon, germanium, etc., the resistance decreases with increase in temperature.
संबंधित प्रश्न
If the equivalent resistance is to be increased, then the number of resistances should be connected in
- Series
- Parallel
- Mixed arrangement
- None of the above
A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R’, then the ratio `"R"/"R'"` is ______.
The substance having infinitely high electrical resistance is called:
(a) conductor
(b) resistor
(c) superconductor
(d) insulator
Write down an expression for the resistance of a metallic wire in terms of the resistivity.
Calculate the resistance of an aluminium cable of length 10 km and diameter 2.0 mm if the resistivity of aluminium is 27 × 10−8 Ωm.
Three resistors of 6.0 Ω, 2.0 Ω and 4.0 Ω are joined to an ammeter A and a cell of emf 6.0 V as shown in the following figure. Calculate :
- the effective resistance of the circuit.
- the reading of ammeter.
Why are thick copper wires used as connecting wires?
Write an expression for the resistance of a conducting wire in terms of its length and area of cross-section.
Calculate the quantity of heat that will be produced in a coil of resistance 75 Ω if a current of 2A is passed through it for 2 minutes.
What is the maximum resistance which can be made using five resistors each of `1/5` W?
