Current Electricity Concepts

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Questions and Answers

What are the minimum requirements to cause the flow of current?

A voltage source, a conductor and an insulator

A voltage source and a conductor (correct)

A voltage source, an ammeter, a conductor

A voltage source, a switch and a resistor

Out of the following, select the best conductor of electricity.

None of these

China clay

Graphite (correct)

Porcelain

Which of the following statements is correct?

The resistance of a conductor is the hindrance by which the conductor opposes the flow of the current. (correct)

The resistance of a wire does not depend upon its material.

The resistance does not play an important role in electrical engineering.

The resistance of most of the materials is independent of the temperature.

Resistance of a conductor increases when:

Its length increases Signup and view all the answers

The specific resistance ρ depends upon:

The material of the conductor, its area of cross-section and length Signup and view all the answers

The specific resistance ρ is defined as:

Resistance of a conductor which has a length of 1 m and cross-section of 1 cm² at 20°C Signup and view all the answers

The resistance of a conductor, when its temperature is increased:

Increases Signup and view all the answers

It was experimentally found by James Prescott Joule that the heat produced in a current carrying conductor is proportional to:

The square of the current Signup and view all the answers

The value of Joule’s mechanical equivalent of heat, J, is equal to:

4.2 Joules per calorie Signup and view all the answers

Temperature coefficient of a conductor is defined as the:

Increase in resistance per degree centigrade Signup and view all the answers

When current flows in a conductor, heat is produced because:

Of Joule’s law Signup and view all the answers

Heating effect of current has undesirable side effects in:

Vacuum cleaner Signup and view all the answers

The resistance of carbon (filament in carbon-filament lamps) when its temperature is decreased:

Decreases Signup and view all the answers

The curve representing Ohm’s law is:

Linear Signup and view all the answers

The condition in Ohm’s law is that:

The temperature should remain constant Signup and view all the answers

Ohm’s law does not apply to:

Semiconductor Signup and view all the answers

Ohm’s law is applicable to:

None of these Signup and view all the answers

Study Notes

Current Electricity

To cause the flow of current you need a voltage source and a conductor.
Graphite is the best conductor of electricity out of the options given.
Resistance is the opposition to the flow of current within a conductor.
The resistance of a conductor increases when its length increases and decreases when its area increases.
Specific resistance (ρ) depends only on the material of the conductor.
Specific resistance (ρ) is defined as the resistance of a conductor that has a length of 1 m and a cross-section of 1 cm2 at 20oC.
When the temperature of a conductor is increased its resistance increases.
James Prescott Joule found that the heat produced in a current carrying conductor is proportional to the square of the current.
Joule’s Mechanical Equivalent of Heat (J) is 4.2 Joules per calorie.
Temperature coefficient of a conductor is defined as the increase in resistance per degree Celsius.
Heat is produced when current flows in a conductor due to collisions between electrons and atoms.
The undesirable side effect of the heating effect of current is the loss of energy.
The resistance of carbon (filament in carbon-filament lamps) decreases when its temperature decreases.
The graph representing Ohm’s law is a straight line.
The condition for Ohm’s law is that the temperature remains constant.
Ohm’s law does not apply to semiconductors.
Ohm’s law applies to conductors in a constant temperature environment.

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Description

This quiz covers essential concepts of current electricity including the role of voltage sources, conductors, resistance, and specific resistance. It also explores the effects of temperature on conductivity and Joule's findings regarding heat production in conductors. Test your understanding of these foundational principles of electricity!