Evaluate the experiment below, identifying energy loss and errors, and access their effect on the efficiency?The experiment was 'Determining the efficiency of energy conversion of boiling water in...

Evaluate the experiment below, identifying energy loss and errors, and access their effect on the efficiency?

The experiment was 'Determining the efficiency of energy conversion of boiling water in an electric kettle'.

The method/system -

1. Weigh accurately 1000g of water and pour into the kettle provided.
2. Switch on to boil and start the timer. Time how long it takes for the water to boil and record your result.

I calculated the amount of energy used to make the water boil to be -334.4 KJ.

I calculated the 'efficiency' of energy inter-conversion of the system to be 77.4%.

Evaluate the experiment above, identifying energy loss and errors, and access their effect on the efficiency?

THANK YOU!

Asked on by sarahh10

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neela's profile pic

neela | High School Teacher | (Level 3) Valedictorian

Posted on

The details of  the experiment is given partially.

It requires information of energy imput given to the system . We suppose it depends on the time , and you calculated correctly, and the energy is E say. (but you did not mention what is E.

The quantum of heat utilsed by 1000 g of water could easily calculated if the initial temerature of the water before heating  and at the boiling point are given. The energy is the product of mass of water and the difference temperature in Kelvin  and 4.186/1000 K Joule.

Make an allowance for the kettle's energy raise as it also raises in temperature.

So the efficiency of the inter conversion is = {Energy due to raise in temperature of kettle+energy utilised by 1000 g water to raise its temperature to boiling point)/supplied enrgy}*100 %.

Therefore the energy loss = (100-efficiency in percent)%

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