10.18-10.31 Current and energy part 2

Question 1

How does resistance change with a filament lamp?

Answer 1

.Greater intensity of light, lower the resistance

Question 2

How does resistance change when a diode is added?

Answer 2

.Allows low resistance in one direction

.Opposite direction=Very high resistance as it stops current going in one direction

Question 3

How does the resistance of a LDR vary with light intensity?

Answer 3

.Resistance greatest when dark

Question 4

How does the resistance of a thermistor change with temperature?

Answer 4

.Hotter temperatures-resistance is lower

Question 5

What happens when there is an electrical current in a resistor?

Answer 5

.There is a energy transfer which heats the resistor

Question 6

What happens to electrical energy when electrical current does work against electrical resistance?

Answer 6

It dissipates as thermal energy in the surroundings

Question 7

What is the energy transfer from electrical energy to thermal energy a result of?

Answer 7

Collisions between the electrons and ions in the lattice

Question 8

How could you reduce energy transfer?

Answer 8

Use low resistance wires

Question 9

Give two disadvantages of heating effect on a electrical current

Answer 9

.Production of excessive amounts of heat in a circuit can be dangerous
.Poorly maintained devices could catch fire

Question 10

What is power?

Answer 10

The energy transferred per second

Question 11

What is the power transfer in any circuit related to?

Answer 11

.The potential difference across it and current in it