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7th Form > Electromagnetism > Flashcards

Flashcards in Electromagnetism Deck (13)
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1
Q

Describe an experiment to validate Faraday’s Law

A

Setup a magnet on a variable speed motor, near a coil connected to an oscilloscope. Vary speed of rotation, expect to see amplitude increase and period decrease. Measure maximum EMF, use V/cm scale setting. Measure peak to peak distance on graticule, use s/cm time base setting. Record V, T and calculate f = 1/T. Plot V vs f and see straight line through origin.

2
Q

Define magnetic flux density (magnetic field strength).

A

magnetic flux in an area taken perpendicular to the magnetic flux’s direction

3
Q

What rule is used to determine the direction of the force experienced b a current-carrying conductor in a magnetic field?

A

Fleming’s left-hand rule.

4
Q

What is 1 Tesla?

A

When a wire carrying a current of 1 ampere placed perpendicular tto the magnetic field experiences a force of 1N per meter of its length.

5
Q

State Faraday’s law.

A

The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux linkage.

6
Q

State Lenz’s law.

A

The direction of the induced emf or current is always such as to oppose the change producing it.

7
Q

State the equation linking force, flux density, current and length

A

F=BIL

8
Q

What is magnetic flux?

A

A measure of the magnetic field strength, draw as a set of lines whose density is proportional to the field
strength. Measured in Webers (Wb).

9
Q

What is 1 Weber?

A

The number of flux lines through a 1m^2

area in a field of strength 1T

10
Q

What is magnetic flux linkage?

A

The product of the magnetic field strength and the number of turns in a coil.

11
Q

What is electromagnetic intensity?

A

The electromagnetic power per unit area.

12
Q

What is a continuous spectrum?

A

A spectrum in which all visible frequencies or wavelengths are visible.

13
Q

What is a photon?

A

A quantum of electromagnetic energy.