power

Question 1

What is power?

Answer 1

The rate of energy transfer/ rate of doing work (E/t)

Question 2

Why does a moving charge transfer electricity?

Answer 2

when it does work (transfers energy) against the resistance of a circuit

Question 3

Explain how a kettle is designed to transfer energy to components in the circuit when a current flows.

Answer 3

-kettle transfers energy electrically from the mains ac supplpy to the thermal energy store of the heating element inside the kettle

Question 3

Why do not all appliances transfer ALL energy completely usefully?

Answer 3

Because the higher the current, the more energy is transferred to the thermal energy store of thee components + surroundings.

Question 4

What is a power rating?
Why does it matter?

Answer 4

A label that is on most appliances that say the maximum safe power they can operate at ( its maximum operating power)
Helps customers choose between models; lower power rating;less electricity and appliance uses in agiven time so thee cheaper it is to run

Question 5

What happens when an eleectrical charge goes through a change in potential difference?

Answer 5

energy is transferred
-energy is supplied to the charge at the power source to raise it through a potential, the charge gives up this energy when it falls through any potential drop in components elsewhere in the circuit

Question 6

What is the Equation to do with charge and energy transferred.

Answer 6

E=QV

Question 8

What can be inferred form the equation linking charge, energy transferred and pd?

Answer 8

a battey with a bgger pd will supply more energy to the circuit for every coloumb of charge which flows round it, because the charge is raised up higher at the start.

Question 9

What links Power and Current and PD
what about power and resistance and current?

Answer 9

P=VI
P=RI^2