Question

If a student while studying the dependence of current on the potential difference keep the circuit closed for a long time to measure the current and potential difference, then,
a) ammeter’s zero error will change
b) ammeter will give more reading
c) voltmeter will show constantly higher readings
d) resistor will get heated up and its value will change.

Answer 1

Hint: If a student can hold the circuit closed for an excellent time the resistor will get warmed up, and its value will vary. This is because of the heat generated in a resistor. The heat generated in a circuit is provided by heat is directly proportional to the heat as time will rise heat generated in the circuit increases. Hence the resistor will get burned up due to which its value will vary.

Complete step-by-step solution:
If a student studying the connection of current or potential difference holds the circuit closed for high, then the resistor's value will vary as it warms up.
We know that: -
According to Ohm's law, the potential difference over the edges of a resistor is directly proportional to the current through it, producing its temperature persisting the same. That is
$V \propto I$
$V = IR$
Here R is a fixed for the given resistor at a provided temperature and is termed its resistance. The resistance Ohm is its SI unit. A graph among the potential difference over the two edges of a resistor and its current is a straight line moving by the origin. The inclination of this graph provides the resistance R of the resistor. To verify Ohm's law, we estimate the potential difference across the two points of a resistor at various currents into it in an electric circuit. The current by the resistor is estimated by joining an ammeter in series with it. The potential difference between the resistor's two ends is measured by combining the voltmeter in parallel with it.
Hence, if a student, while examining the current dependence on the potential difference, remains the circuit closed for a great time to estimate the current and potential difference. Then current running for a long time may heat the resistor, and subsequently, its value can fluctuate due to a temperature change.
Option (d) is correct.

Note:The electrical resistance of conductors depends upon the manner of collision among the electrons within the substance. When the temperature rises, the process of electron collision grows rapidly and faster. As a consequence, the resistance will rise with the increase in the temperature of the conductor.