Topic 7

Question 1

What is an electric field

Answer 1

A space that causes charged particles to accelerate

Question 2

What is the electric field strength

Answer 2

The force on the charged particle by the electric field

Question 3

What is the electric field strength equation

Answer 3

F=EQ
N = N/C * C
N=newton
C=coulomb

Question 4

How can newtons second law be combined with electric field strength

Answer 4

F=ma AND F=EQ (same as F=Ed)

a=EQ/m (Force=efs*distance)

Question 5

Each particle in a field has a potential, how can this potential be found

Answer 5

E=VQ
N/C = V*C
Newtom per Coulomb = Voltage * Coulomb

Question 6

How do you measure the distance of a uniform electric field

Answer 6

d=V/E

Question 7

What are equipotentials

Answer 7

Positions in a electric field with zero potential difference between them

Question 8

What is a radial field

Answer 8

A region around a charged sphere where an electric field acts either towards the sphere or away from the sphere

Question 9

What happens to electrical field energy as you move away from the center

Answer 9

Decreases and the distance between equipotentials also decrease

Question 10

How does a capacitor work?

Answer 10

Electrons move away from the positive place through the cell and onto the negative plate

Question 11

What does the area under a capacitor give?

Answer 11

Work done

Question 12

What is capacitance

Answer 12

The measure of capability of a capacitor

Question 13

What happens to the rate of capacitance discharge when more charge is stored?

Answer 13

The rate decreases

Question 14

What is the time constant, and what equation is used?

Answer 14

The overall rate of discharge, tells us how long it will take in seconds for the capacitance to discharge by 37%

τ = RC

Question 15

What is magnetic flux

Answer 15

Phrase used for magnetic field lines

Question 16

What is a magnetic field

Answer 16

A space that will cause a magnetic pole to feel a force

Question 17

What is magnetic flux density

Answer 17

The magnetic field strength in teslas

Question 18

What is flux linkage

Answer 18

The amount of magnetic flux interacting with a coil of wire

Question 19

What is quantity of flux

Answer 19

Φ

Question 20

What is the equation for flux linkage

Answer 20

ΦN or ΦBAN

Question 21

What is flemings left hand rule?

Answer 21

Thumb = motion
Index = field
Middle = current

Question 22

Flemings right hand rule, what is it?

Answer 22

Thumb = motion
Index = field
Middle = EMF

Question 23

What is the equation F=BILsinθ used for

Answer 23

Force on a wire or motor

Question 24

What is F=Bevsinθ used for

Answer 24

Force on a charged particle

Question 25

What is electromagnetic induction

Answer 25

Electrons in a wire also feel the magnetic field and will cause them to move creating an emf

Question 26

What is faradays law?

Answer 26

Induced emf is proportional to rate of change of flux

Question 27

What is lenzs law?

Answer 27

Moving a magnet through a wire magnetic or non magnetic will create an emf

Question 28

What is AC

Answer 28

Alternating current is when a coil is rotated in a magnetic field creating an emf that constantly changes the direction of current

Question 29

Can AC have a frequency? If so why and what els does this form

Answer 29

Yes because it has cycles creating a waveform

This form peak values for I and V

Question 30

How is the voltage and current for AC determined

Answer 30

V=Vo/root2 same for I

Question 31

How do transformers work?

Answer 31

Current passes though a primary coil which has more coils so more voltage and this generates a magnetic field in an iron core. The iron core will carry a magnetic field. The secondary coil is wrapped around less and will produce a lower voltage

Vprimary / Vsecondary = Nprimary / Nsecondary
Voltage in / V out = Number of coils left / No coils right