Electricity

Question 1

What are charge carriers?

Answer 1

Electrons (or ions if in a molten ionic solution)

Question 2

Define current.

Answer 2

It is the rate of flow of charge.

Question 3

Define current mathematically.

Answer 3

I = Q/t current = charge/time

Question 4

Define potential difference

Answer 4

It is the work done per unit charge. V= W/Q

Question 5

Resistance is what?

Answer 5

p.d./current . It is a measure of difficulty of making current pass through a component.

Question 6

State Ohm’s law.

Answer 6

The potential difference across a metallic conductor is proportional to the current through it provided the physical conditions do not change.

Question 7

Power = ?

Answer 7

Current x Voltage (or equivalent)

Question 8

State the equation for resistivity?

Answer 8

p = RA/L where A = cross sectional area of the wire.

Question 9

Current in a series circuit is the same / different throughtout?

Answer 9

SAME.

Question 10

Psycology is not a

Answer 10

science

Question 11

The rule for resistance across a series circuit?

Answer 11

R = R₁ + R₂ + R₃ + … = ΣR

Question 12

The rule for resistance across a parralel circuit?

http://www.bbc.co.uk/staticarchive/f05ff5a203852005e54ec82ee35181d516a52d4b.gif

Answer 12

R = R₁^-1 + R₂^-1 + R₃^-1 + …