Electromagnetism

Question 1

Define Magnetic Field

Answer 1

Question 2

Define Magnetic Field Line

Answer 2

Question 3

How can you map field lines around a magnet/

Answer 3

Question 4

How do you represent the strength of a Magnetic Field on a diagram?

Answer 4

Question 5

Define Magnetic flux Density

Answer 5

Question 6

What is the unit of Magnetic Flux Density?

Answer 6

Question 7

Why does a compass point to the North Pole of the Earth?

Answer 7

Question 8

How do you work out the shape of the field around a current-carrying wire?

Answer 8

Question 9

How do you work out the shape of the field around a solenoid?

Answer 9

Question 10

What does the Magnetic Field around a flat, circular coil look like?

Answer 10

Question 11

How can you predict which direction the force will push the conductor?

Answer 11

Question 11

Define the motor effect

Answer 11

Question 12

Give the formula relating magnetic force, flux density, current, length and angle between the field and the conductor

Answer 12

Question 13

Describe an experiment to measure flux density

Answer 13

Question 14

What does the setup look like for the experiment to measure flux density?

Answer 14

Question 15

What is the formula for the magnetic force on a moving charge at 90 degrees to the field lines?

Answer 15

Question 16

How is F=BQv derived?

Answer 16

Question 17

Why do charged particles move in a circular orbit in a Magnetic Field?

Answer 17

Question 18

How can you derive the formula for the radius of the circular orbit?

Answer 18

Question 19

Answer 19

Question 20

What is the purpose of a velocity selector?

Answer 20

They isolate particles of a specific velocity. This is useful for things like mass spectrometry.

Question 21

How does a velocity selector work?

Answer 21

Question 22

Define Magnetic Flux

Answer 22

Question 23

What is the unit for Magnetic flux?

Answer 23

Question 24

What is the formula for Magnetic Flux?

Answer 24

Question 25

Define Magnetic Flux linkage

Answer 25

Question 26

State Lenz’s law

Answer 26

Induced emf is always in a direction as to oppose the change that caused it.

Question 27

Explain Lenz’s law in terms of energy.

Answer 27

Question 28

State Faraday’s Law

Answer 28

Question 29

what is the formula that links Faraday’s law and Lenz’s law?

Answer 29

Question 30

What is a search coil?

Answer 30

Question 31

How can you measure magnetic flux using a search coil?

Answer 31

Question 32

What is the structure of a simple A.C. generator?

Answer 32

Question 33

How does a simple A.C generator work?

Answer 33

Question 34

How do emf and flux linkage vary in a sample A.C. generator? (graphs)

Answer 34

Question 35

How can the peak emf of an A.C. generator be increased?

Answer 35

Question 36

What is the purpose of a transformer?

Answer 36

Question 37

Describe the structure of a simple transformer.

Answer 37

Question 38

How does a transformer work?

Answer 38

Question 39

Give the formula that relates the number of turns with the potential difference of each coil.

Answer 39

Question 40

For an ideal transformer (100% efficient), give the formula relating potential difference and current in both coils.

Answer 40

Question 41

What role do step-up transformers play in the National Grid?

Answer 41

Question 42

Answer 42

Question 43

How can you investigate the efficiency of a transformer?

Answer 43