Moving Charge

Question 1

Define current

Answer 1

The rate of flow of charge

Question 2

As more electrons build up, what happens to the resistance?

Answer 2

Resistance increases

Question 3

What should the gradient of a charge-time graph be equal to?

Answer 3

Current

Question 4

What are the units and base units for t, I, Q

Answer 4

t - s - s

I - nA - A

Q - nC - As

Question 5

What is the area under graph of a current vs time graph equal to?

Answer 5

Charge

Question 6

How does the flow of conventional (DC) current differ from the flow of electrons?

Answer 6

Conventional current flows from positive to negative

Flow of electrons is from negative to positive (opposite to flow of current)

Question 7

What is ‘e’ and its unit (in a current in a wire diagram)?

Answer 7

‘e’ is the charge on an electron

Measured in coulombs (C)

Question 8

What is ‘Q’ and its unit (in a current in a wire diagram)?

Answer 8

‘Q’ is the charge on an ion

Measure in coulombs (C)

Question 9

What is ‘v’ and its unit (in a current in a wire diagram)?

Answer 9

‘v’ is drifting velocity

Measured in ms^-1

Question 10

What is ‘n’ and its unit (in a current in a wire diagram)?

Answer 10

‘n’ is number of ions per unit volume

Measured in m^-3

Question 11

What is ‘A’ and its unit (in a current in a wire diagram)?

Answer 11

‘A’ is cross sectional area

Measured in m^2

Question 12

What is ‘I’ and its unit (in a current in a wire diagram)?

Answer 12

‘I’ is current

Measured in amps (A)