# EMF on cable moving in magnetic field

• amiemgm
In summary, the conversation is about a question posted by a teacher regarding a drop cable system that creates an induced EMF by moving through a magnetic field. The team drops a 30.0 km-long cable from a space shuttle orbiting at 8.00 x 103 m/s, with an earth magnetic field of 6.50 x 10-5 T. The motional EMF induced between the ends of the cable is 1.44 V, with the angle between the cable and magnetic field at 90 degrees. To estimate the electrical power that can be provided to a satellite, one would need to know the cable's resistance, current, and voltage. Assuming reasonable values, the estimated power is 2 Watts.
amiemgm

## Homework Statement

Our teacher just posted this question online. We have less than an hour to figure it out. Can someone help point me in the right direction.

Your team has devised an orbiting “drop cable”
system that creates an induced EMF by moving a cable through a
magnetic field. In a test, tour team drops a 30.0 km-long cable from the
space shuttle, orbiting at a speed of 8.00 x 103 m/s. The magnitude of
the earth’s magnetic field at the shuttle’s location in about 6.50 x 10-5 T.
a) Find the motional EMF induced between the ends of the cable.
Assume, and state, what the angle should be between the cable and the
magnetic field to get the largest EMF. b) If you are to estimate the
electrical power that can be provided to a satellite, what else would you
need to know? Assume a reasonable value for any unknown (Check
with instructor.) and estimate this power.

## Homework Equations

Not sure? We just start this section today.

## The Attempt at a Solution

a) The equation for the motional EMF induced between the ends of the cable is EMF = vBL, where v is the speed of the cable, B is the magnetic field, and L is the length of the cable. Therefore, EMF = 8.00 x 103 m/s * 6.50 x 10-5 T * 30.0 km = 1.44 V. To get the largest EMF, the angle should be 90 degrees between the cable and the magnetic field. b) To estimate the electrical power that can be provided to a satellite, you would need to know the resistance of the cable, the current in the cable, and the voltage across the cable. Assuming the resistance of the cable is 0.1 Ohms, the current is 1.44 Amps, and the voltage across the cable is 1.44 Volts, then the estimated power is 2 Watts.

## 1. What is EMF?

EMF stands for electromagnetic force or electromotive force. It is a measure of the electric potential difference between two points in a circuit, caused by the movement of charged particles.

## 2. How is EMF created on a cable moving in a magnetic field?

When a cable is moved through a magnetic field, the magnetic field exerts a force on the charged particles in the cable, causing them to move. This movement of charged particles creates a difference in electric potential, resulting in an EMF.

## 3. What are the factors that affect the amount of EMF generated on a cable moving in a magnetic field?

The amount of EMF generated on a cable moving in a magnetic field depends on the strength of the magnetic field, the speed of the cable's movement, the length of the cable, and the angle between the cable and the magnetic field.

## 4. How is EMF measured on a cable moving in a magnetic field?

EMF can be measured using a device called a voltmeter. The voltmeter is connected to the ends of the cable, and it measures the potential difference or voltage created by the EMF.

## 5. What are the applications of EMF on a cable moving in a magnetic field?

EMF generated on a cable moving in a magnetic field is used in many devices, such as generators, motors, and transformers, to convert mechanical energy into electrical energy or vice versa. It is also used in various industrial and scientific processes, such as induction heating and electromagnetic levitation.

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