Current Electricity

Question 0

Define the coulomb

Answer 0

The amount of charge that passes in one second when the current is one ampere

Question 1

Describe in words how current and charge are related

Answer 1

Current is the rate of charge flow

Question 2

Define potential difference

Answer 2

Energy per unit charge

Question 3

Name one environmental factor likely to alter the resistance of a component

Answer 3

Temperature

Question 4

What is special about an ohmic conductor?

Answer 4

Resistance is constant

Question 5

Sketch the circuit used to determine I/V characteristics of a component

Answer 5

Power source
Ammeter
Component with voltmeter connected in parallel over it
Variable resistor

Question 6

Draw an I/V characteristic graph for a diode

Answer 6

Sharp increase in gradient after 0.6V

Question 7

What is an LDR?

Answer 7

Light-dependant resistor

As light intensity increases, resistance decreases

Question 8

If an I/V graph is curved, what does it tell you about the resistance?

Answer 8

The resistance changes

Question 9

What happens to a superconductor when it’s cooled to its transition temperature?

Answer 9

Its resistance hits zero

Question 10

What three factors does the resistance of a length of wire depend on?

Answer 10

Resistivity of the wire material
Length of the wire
The wire’s cross-sectional area

Question 11

What are the units for resistivity?

Answer 11

Ohm meters

Question 12

Write down the equation linking power, current and resistance

Answer 12

P=RI^2

Question 13

What equation links power, voltage and resistance?

Answer 13

P=(V^2)/R

Question 14

Power is measured in watts. What is 1 watt equivalent to?

Answer 14

1 joule per second

Question 15

What causes internal resistance?

Answer 15

In a battery, chemical energy is used to make electrons move. As they, move, they collide with atoms inside the battery. Thus, batteries must have resistance