Resistance

Question 1

An electric current is…

Answer 1

A flow of electrons through a conductor(such as a metal wire)

Question 2

As electrons move through the _____, they collide with other ____ in the metal

Answer 2

As electrons move through the conductor, they collide with other atoms in the metal

Question 3

Where/what can electric energy be transferred to in a circuit?

Answer 3

other forms of energy e.g. thermal

Question 4

What does the resistance tell us?

Answer 4

The resistance tells us the p.d required to drive a current through a component (how much energy required to push a coulomb of charge through).

Question 5

A lamp has a current of 1A and a voltage of 1V
Does this lamp have a lower or higher resistance than a lamp with a current of 1A and a voltage of 10V?
Explain why.
What about lamp B? higher or lower? why?

Answer 5

Lower resistance
Less energy is needed to drive the current through lamp a than lamp B
Lamp B takes more energy to drive the current through the lamp, this means lamp B a higher resistance.

Question 6

what is current measured in? Give the unit.

Answer 6

Ampere/ amps. (A)

Question 7

what is potential difference measured in? Give the unit.

Answer 7

Volts, V

Question 8

What is resistance measured in?

Answer 8

Ohm

Question 9

what is the unit for resistance?

Answer 9

Ω

Question 10

what is the equation for resistance?

Answer 10

R = V/I

Resistance( Ω )= potential difference(V) / current(A)

Question 11

A lamp has a p.d of 1V and a current of 1A. Calculate the resistance.

Answer 11

1Ω
Resistance( Ω )= potential difference(V) / current(A)
Resistance( Ω )= 1V / 1A = 1Ω

Question 12

A lamp has a p.d of 1V and a current of 10A. Calculate the resistance.

Answer 12

10Ω
Resistance( Ω )= potential difference(V) / current(A)
Resistance( Ω )= 10 / 1A = 10Ω