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प्रश्न
What is a resistance? Define it with respect to Ohm’s law,
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उत्तर
In the flow of current in a conductor, electrons are drifted. During this drift or flow, electrons mutually collide against each other and the atoms of the conductor. These collisions give rise to some obstruction to the flow of electrons. This opposition or obstruction offered by a conductor to the flow of electrons is called ‘Resistance’. According to Ohm’s law, the ratio between potential difference V and the current i, is a constant provided the temperature and physical conditions of the conductor remain unaltered. As such the ratio V/I is called the resistance, i.e., ‘Ohmic resistance’ of the conductor.
संबंधित प्रश्न
The V-I graph for a series combination and for a parallel combination of two resistors is shown in the figure below. Which of the two A or B. represents the parallel combination? Give reasons for your answer.
How does the resistance of a wire change when:
its length is tripled?
The diagram below shows part of a circuit:
If this arrangement of three resistors was to be replaced by a single resistor, its resistance should be:
(a) 9 Ω
(b) 4 Ω
(c) 6 Ω
(d) 18 Ω
Draw a V-I graph for a conductor at two different temperatures. What conclusion do you draw from your graph for the variation of resistance of conductor with temperature?
Name the following substances:
(i) Showing low resistivity,
(ii) Showing very high resistivity,
(iii) Showing moderate resistivity.
You have three resistors of values 2 `Omega`, 3 `Omega`, and 5 `Omega`. How will you join them so that the total resistance is less than 2 `Omega`?
Calculate the equivalent resistance of the following combination of resistor r1, r2, r3, and r4
A given metallic wire of resistance R is doubled on itself. What will be its new resistance?
Why are thick copper wires used as connecting wires?
In the circuit shown below, calculate the equivalent resistance between the points (i) A and B, (ii) C and D.
