Unit of Resistance Important Questions

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Resistance can be defined as a physical property of a material in which, the material can resist the flow of electricity. The resistance mostly depends upon the physical dimensions, composition, and temperature of the material. Resistance is denoted by the letter ‘R’. The SI unit of resistance is Ohm.

Important Questions On Unit Of Resistance

Ques. What is the SI unit of resistance? (1 Mark)

Ans. The SI unit of resistance is Ohm.

Ques. Define Resistance. (1 Mark)

Ans. Resistance can be defined as a physical property of a material in which, the material can resist the flow of electricity. The resistance mostly depends upon the physical dimensions, composition, and temperature of the material. Resistance is denoted by the letter ‘R’. The SI unit of resistance is Ohm.

Ques. Define the unit of resistance. (1 Mark)

Ans. The SI unit of resistance Ohm is the resistance of a conductor when a current of 1 A flows through it because of a potential difference of 1 V.

Ques. Is resistance and resistivity different term? (1.5 Marks)

Ans. The resistance and resistivity quantify the number of difficulties provided by a material to the flow of electricity. The resistance between the ends of a wire is the total ratio of the potential differences between the two points to the current flowing through the conductor.

The resistivity of a material is defined as the resistance of two units i.e., unit length and unit cross-section of that material. Hence, resistivity is measured in terms of Ohm-meter.

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Ques. What is the dimension of a unit of resistance? (1 Mark)

Ans. The dimension of a unit of the formula is [M] [L2][T-3][1-2]

Ques. Why is the resistance of the voltmeter high? (2 Marks)

Ans. The voltmeter has high resistance to avoid the effects of loading. When the resistance of the voltmeter is low, it starts acting as a load and draws current from the source. A voltmeter is connected in parallel to the load, and the current drawn by the actual load also has some changes.

Whereas, a voltmeter with very high resistance, draws a very low value of current from the source and the load current is the same similar to without the voltmeter. Hence, the voltage across the load is approximately the same and we get the correct voltage reading.

Ques. what are the external resistance and internal resistance? (2 Marks)

Ans. Internal resistance is resistance within a battery, or another voltage source, which causes a drop in the source voltage when there is a current. And external resistance is generally referred to as the opposition to the flow currently offered by any load.

Ques. What is a function of resistance? (1.5 Marks)

Ans. The functions of resistance is:

The resistance limits the current, or in many cases, regulates the current if the source of voltage provides a constant voltage.
Resistance can consume power and then converts it into heat.

Ques. Why is resistance so important? (2 Marks)

Ans. The resistance of a conductor is important, as it controls the flow of current in the circuit.

Eg. according to ohm’s law; zero resistance of a circuit will have an infinite current value.

I = V/R

On putting 0 in R

1=V/0

Hence, it is a dangerously high current.

Ques. State a relation between current and resistance. (1.5 Marks)

Ans. The relation is inversely proportional.

The increases in resistance cause a decrease in current and the decrease in current causes increases in current.
When resistance is doubled, the current is halved and if resistance is increased 5 times, the current is decreased 5 times. So now when resistance is halved, the current doubles.

Also Check:

Study Guides
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Important Physics Constants	NCERT Class 12 PCMB Textbook	SI Units in Physics
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NCERT Solutions for Class 12 Chemistry	NCERT Solutions for Class 12 Biology	NCERT Solutions for Class 12 Physics
Class 12 English Book Pdf	NCERT Solutions for Class 12 Chemistry	Important Physics Formulae
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