C22 (Electric Fields)

Question 1

Electric Field Definition

Answer 1

The area around object, which a charge would experience a force

Question 2

Electric field strength definition

Answer 2

Force per unit positive charge

Question 3

Equation for EFS

Answer 3

Force / Positive Charge

Question 4

Electric field Patterns:

Answer 4

Arrow, direction
Right angle to surface of conductor
Parallel lines if uniform field
Closer lines = greater EFS

Question 5

Definition 1C

Answer 5

Amount charge, passing given point, per second, when current = 1A

Question 6

What are all charges a multiple of?

Answer 6

1.6x10^-19
Quantised

Question 7

The force between 2 electric charges (Q&q) are proportion to what, and inversely proportional to what?

Answer 7

Proportional to Qxq
Inversely proportional to square of separation (r)

Question 8

Force is directly proportional to…

Answer 8

Qq/r^2

Question 9

Electric field strength defined as…

Answer 9

The force per unit positive charge

Question 10

What is the change in work done equal to

Answer 10

Change in potential energy
Mass x change in gravitational potential

Question 11

The change of energy potential equation

Answer 11

m x g x change h

Question 12

Equation for no. excess electrons:

Answer 12

Q (charge) / e (electron charge)

Question 13

Electric field strength is inversely proportional to what

Answer 13

r^2 (double distance, EFS decreases by a factor of 4).

Question 14

Electric potential equation

Answer 14

EPE = Vq = Qq / 4pi x epsilon 0 x r

Question 15

How do you derive the equation C=4pi x epsilon 0 x r
From V = Q / C

Answer 15

V = Q / C
Sub V = Q / 4pi x epsilon 0 x r into the equation above
Cancels Q on both sides
Leaving you with C = 4pi x epsilon 0 x r

Question 16

What’s the differences between electric fields and gravitational fields (2):

Answer 16

• Objects can be shielded from electric fields, but not gravitational fields.

-The size of electric field depends on medium between the charges, for gravitational fields strength this makes no difference.

Question 17

Electrical potential (definition):

Answer 17

Work done bringing a unit charge from infinity to a (specific) point.

Question 18

What’s the equation of the force exerted by an electron?

Answer 18

Force = energy (electron) x Q (e)

Question 19

Equation for work done (by an electron):

Answer 19

Volts x q
Work done = Ve

Question 20

Electric potential equation:

Answer 20

V = W / Q

Question 21

How to work out the acceleration of an electron?

Answer 21

a = F / m
F = E (energy) x Q