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I hope you don't mind me posting these questions here, but I just can't figure these physics assignments out and would really appreciate some help. Thank you in advance!

 

1. With a kettle, Peter warms up 1,2 litres of water (20°C) till it starts to boil. The power of the kettle is 2000 W. The heating up takes four minutes. The formula for specific heat of the water is 4,2 J/g · °C. How high is the efficiency of the kettle?

 

A. 48%

B. 69%

C. 84%

D. 99%

E. 119%

 

 

2. A kettle can contain 1,4 litres of water. The device has a power of 2000 W. The formula for specific heat of the water is 4,2 J/g · °C and the density is 1,0 g/mL. Calculate how long it would take before the kettle filled to the brim with water (20°C) would be boiling.

 Jun 21, 2019
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1. With a kettle, Peter warms up 1,2 litres of water (20°C) till it starts to boil. The power of the kettle is 2000 W. The heating up takes four minutes. The formula for specific heat of the water is 4,2 J/g · °C. How high is the efficiency of the kettle?

2. A kettle can contain 1,4 litres of water. The device has a power of 2000 W. The formula for specific heat of the water is 4,2 J/g · °C and the density is 1,0 g/mL. Calculate how long it would take before the kettle filled to the brim with water (20°C) would be boiling.

 

Q = E

laugh

 Jun 21, 2019
edited by Omi67  Jun 21, 2019
edited by Omi67  Jun 21, 2019
edited by Omi67  Jun 21, 2019

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