Magnetic Field Lines Around a Conducting Wire

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Questions and Answers

What happens to the magnitude of the magnetic field produced at a given point if the current through the wire increases?

It becomes zero

It increases (correct)

It decreases

It remains the same

The direction of magnetic field lines is reversed if the direction of current through the straight copper wire is reversed.

True

What happens to the deflection of the compass needle if the compass is moved away from the copper wire but the current through the wire remains the same?

The deflection in the needle decreases.

The concentric circles representing the magnetic field around a current-carrying straight wire become larger and larger as we move away from the _______________________.

wire Signup and view all the answers

What is the effect of increasing the current in the wire on the deflection of the compass needle?

Increases the deflection Signup and view all the answers

The magnetic field produced by a given current in the conductor remains the same as the distance from it increases.

False Signup and view all the answers

Match the following statements with the correct outcome:

Increasing the current in the wire = Increases the deflection of the compass needle Decreasing the current in the wire = Decreases the deflection of the compass needle Moving the compass away from the wire = Decreases the deflection of the compass needle Reversing the direction of current in the wire = Reverses the direction of magnetic field lines Signup and view all the answers

What is the effect of reversing the direction of current through the straight copper wire on the direction of magnetic field lines?

The direction of magnetic field lines is reversed. Signup and view all the answers

What happens to the direction of force acting on the current-carrying rod when the poles of the magnet are interchanged?

The direction of force gets reversed Signup and view all the answers

The direction of force on the conductor depends only on the direction of current.

False Signup and view all the answers

What is Fleming's left-hand rule?

Fleming's left-hand rule is a simple rule to find the direction of the force on the conductor. It states that if the first finger points in the direction of the magnetic field and the second finger in the direction of current, then the thumb will point in the direction of motion or the force acting on the conductor. Signup and view all the answers

The displacement of the rod is largest when the direction of current is at right angles to the direction of the _______________________ field.

magnetic Signup and view all the answers

An electron enters a magnetic field at right angles to it. What is the direction of force acting on the electron?

to the left Signup and view all the answers

Match the following devices with their uses:

Electric motor = Conversion of electrical energy into mechanical energy Electric generator = Conversion of mechanical energy into electrical energy Loudspeakers = Conversion of electrical energy into sound energy Microphones = Conversion of sound energy into electrical energy Signup and view all the answers

The magnitude of force on the conductor is highest when the direction of current is parallel to the direction of the magnetic field.

False Signup and view all the answers

What is the condition for the maximum displacement of the rod?

The direction of current is at right angles to the direction of the magnetic field. Signup and view all the answers

Which of the following correctly describes the magnetic field near a long straight wire?

The field consists of concentric circles centred on the wire. Signup and view all the answers

What happens to the current in the circuit at the time of short circuit?

It increases heavily. Signup and view all the answers

The earth wire is used as a safety measure to ensure that any leakage of current to a metallic body does not give any severe shock to a user.

True Signup and view all the answers

What is the primary function of a fuse in an electric circuit?

To protect the circuit from short-circuiting or overloading. Signup and view all the answers

The magnetic field of a solenoid carrying a current is similar to that of a _______________________.

bar magnet Signup and view all the answers

Match the following electric power supply components with their descriptions:

Live wire = The wire with red insulation that carries the electric current. Neutral wire = The wire with black insulation that completes the circuit. Earth wire = The wire with green insulation that is connected to the earth for safety. Fuse = A safety device that protects the circuit from short-circuiting or overloading. Signup and view all the answers

What is the frequency of the AC electric power received in houses?

50 Hz Signup and view all the answers

The potential difference between the live wire and the neutral wire is 110 V.

False Signup and view all the answers

What is the purpose of a fuse in an electric circuit?

To break the circuit when it is overloaded Signup and view all the answers

A compass needle is a small magnet with two poles, one pointing towards east and the other towards west.

False Signup and view all the answers

What is the right-hand rule used for?

The right-hand rule is used to determine the direction of the magnetic field around a conductor due to an electric current flowing through it. Signup and view all the answers

Field lines are used to represent a magnetic field, and they are shown closer together where the magnetic field is _______________________.

greater Signup and view all the answers

What is the expected result when an electric oven of 2 kW power rating is operated in a domestic electric circuit (220 V) that has a current rating of 5 A?

The circuit will be overloaded Signup and view all the answers

Match the following statements with the correct description of a magnetic field:

A magnetic field exists in the region surrounding a magnet = Description 1 Field lines are used to represent a magnetic field = Description 2 A metallic wire carrying an electric current has associated with it a magnetic field = Description 3 The pattern of the magnetic field around a conductor depends on the shape of the conductor = Description 4 Signup and view all the answers

What precaution should be taken to avoid the overloading of domestic electric circuits?

To avoid overloading, one should not connect too many appliances to a single socket, and ensure that the total power rating of the appliances does not exceed the current rating of the circuit. Signup and view all the answers

What is the right-hand thumb rule used for?

To determine the direction of magnetic field lines around a current-carrying conductor Signup and view all the answers

The direction of the magnetic field at a point is given by the direction that a south pole placed at that point would take.

False Signup and view all the answers

Two magnetic field lines can intersect each other.

False Signup and view all the answers

What is the direction of magnetic field at a point directly below a horizontal power line carrying current from east to west?

The magnetic field turns clockwise in a plane perpendicular to the wire when viewed from the east end. Signup and view all the answers

The right-hand thumb rule is used to determine the direction of magnetic field lines around a current-carrying _______________.

conductor Signup and view all the answers

What is the pattern of the magnetic field lines produced around a current-carrying straight wire?

Not specified Signup and view all the answers

Match the following terms with their definitions:

Magnetic field lines = Imaginary lines that emerge from the north pole and enter the south pole Right-hand thumb rule = A rule used to determine the direction of magnetic field lines around a current-carrying conductor Current-carrying conductor = A wire or material that carries electric current Signup and view all the answers

The magnetic field lines around a bar magnet are circular.

False Signup and view all the answers

What is the direction of magnetic field at a point directly above a horizontal power line carrying current from east to west?

The magnetic field turns anti-clockwise in a plane perpendicular to the wire when viewed from the east end. Signup and view all the answers

Study Notes

Magnetic Field Around a Current-Carrying Straight Wire

The direction of magnetic field lines around a straight wire can be determined by the right-hand thumb rule.
If the thumb points in the direction of the current, the fingers will wrap around the conductor in the direction of the field lines.
The magnetic field lines form concentric circles around the wire, with the direction of the field lines being clockwise or anti-clockwise depending on the direction of the current.
The magnitude of the magnetic field produced at a given point increases as the current through the wire increases.
The magnetic field produced by a given current in the conductor decreases as the distance from it increases.

Fleming's Left-Hand Rule

Fleming's left-hand rule is used to determine the direction of the force on a current-carrying conductor placed in a magnetic field.
The rule states that if the first finger points in the direction of the magnetic field and the second finger in the direction of the current, the thumb will point in the direction of the force.
The force on the conductor is perpendicular to both the direction of the current and the magnetic field.

Electric Motor and Generator

Devices that use current-carrying conductors and magnetic fields include electric motors, electric generators, loudspeakers, microphones, and measuring instruments.
The electric motor uses the principle of electromagnetic induction to convert electrical energy into mechanical energy.
The electric generator uses the principle of electromagnetic induction to convert mechanical energy into electrical energy.

Safety Measures in Electric Circuits

Two safety measures commonly used in electric circuits and appliances are fuses and circuit breakers.
Fuses are used to protect the circuit from short-circuiting or overloading, while circuit breakers are used to protect the circuit from overloading.
Overloading can occur due to an accidental hike in the supply voltage or connecting too many appliances to a single socket.