Magnetic Forces and Current Flow

This video tutorial explains the concept of magnetic force acting on a current-carrying wire. It covers the basics of current, drift velocity, and the Lorentz force. The tutorial also discusses how to calculate the total charge in a wire using charge carrier density and volume. The main focus is on deriving the formula for the force on a wire and understanding the direction of the force using the right hand rule. Several examples are provided to illustrate the concepts, and a demonstration video from MIT is included.

What happens to a wire when it is connected to a battery and placed in a magnetic field?

• It experiences a magnetic force.

• It stops conducting current.

• It becomes a magnet.

• It generates electricity.

What is the drift velocity in the context of current flow?

• The speed of light in a vacuum.

• The average speed of charge carriers in a conductor.

• The velocity of a magnetic field.

• The speed of sound in air.

Which equation represents the force acting on an individual charge in a magnetic field?

• F = mv^2/r

• F = ma

• F = qE

• F = q(v × B)

How is the total charge in a wire calculated?

• By dividing the current by the resistance.

• By subtracting the magnetic field from the electric field.

• By multiplying the number of charge carriers by the charge of each carrier.

• By adding the voltage and the current.

What is the formula for the force on a current-carrying wire in a magnetic field?

• F = mv^2/r

• F = i × B

• F = iL × B

• F = qE

In the force formula F = iL × B, what does the vector L represent?

• The electric field direction.

• The length of the wire in the direction of the current.

• The magnetic field strength.

• The velocity of the charge carriers.

What is the angle θ in the force formula F = iLB sin θ?

• The angle between the current and the magnetic field.

• The angle between the wire and the battery.

• The angle between the electric field and the magnetic field.

• The angle between the charge carriers and the wire.

How can the direction of the force on a current-carrying wire be determined?

• Using the left-hand rule.

• Using the right-hand rule.

• By measuring the voltage.

• By calculating the resistance.

What happens to the force on a wire if the current and magnetic field are in the same direction?

• The force is maximized.

• The force is zero.

• The force is doubled.

• The force is reversed.

What is the effect of reversing the polarity of the current on the direction of the force?

• The force becomes zero.

• The force magnitude is doubled.

• The force direction is reversed.

• The force direction remains unchanged.