Gcse Physics energy question

I’ve been given a graph with the x axis as time after the kettle was switched on in seconds, and the y axis the temperature.
The question is using the straight line the useful power output of the kettle ( to heat the water up) can be calculated. Explain how
Please help x

(edited 2 years ago)

Reply 1

mqb2766

What do you know about the power and energy needed?

Reply 2

jlcommander

Original post by mqb2766

What do you know about the power and energy needed?

It asks how id use the straight line to calculate useful power out put of the kettle, so i don’t rlly need to know that i think.
But i know the power is 1150 J
And the energy transferred is 155000

(edited 2 years ago)

Reply 3

mqb2766

Original post by jlcommander

It asks how id use the straight line to calculate useful power out put of the kettle, so i don’t rlly need to know that i think.
But i know the power is 1150 J
And the energy transferred is 155000

How is power and energy related?

Reply 4

jlcommander

Original post by mqb2766

How is power and energy related?

power is energy divided by time
and it’s power output that your trying to work out by the graph not sure if it’s acc relevant to one another tho

Reply 5

mqb2766

Original post by jlcommander

power is energy divided by time
and it’s power output that your trying to work out by the graph not sure if it’s acc relevant to one another tho

Power is the rate of change of Energy
The constant gradient part of the graph gives you the rate of change (gradient) of temperature
Energy supplied = mass * specific heat * change in temperature

That should be enough to work things out.

(edited 2 years ago)