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A jug containing 0.250 kg of liquid is put into a refrigerator. Its temperature decreased from 20°C to 15°C. The amount of energy transferred from the liquid was 5,250 J. Calculate the specific heat capacity of the liquid.

specific heat capacity = change in energy ÷ (mass × change in temperature) [1]= 5,250 ÷ (0.250 × 5) [1]= 4,200 J/kg°C [1]
BP
Answered by Benjamin P. • Physics tutor
1902 Views

Explain how Pumped-storage hydropower (PSH) can store energy.

The system consists of 2 reservoirs at different elevations, where the water can flow between them but through a hydroelectric power station. The higher elevation reservoir releases its water at higher energ...
CK
Answered by Chris K. • Physics tutor
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Explain why a smoke alarm works by emitting and detecting alpha radiation instead of gamma or beta radiation.

Alpha radiation isn't very penetrating and so is absorbed and stopped by smoke particles. This causes a change in count rate when there is smoke present. This change in count rate allows the alarm to be trig...
FM
Answered by Fin M. • Physics tutor
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A ball is dropped from a height of 20m. How long does it take for the ball to reach ground?

Use SUVAT. Height is 20m, initial speed is 0m/s, acceleration is 10m/s^2, and you need to find time. Therefore use s = ut + 1/2 at^2, and rearrange to get a value for t as t = 2s.
LT
Answered by Lauren T. • Physics tutor
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What are the changes in energy that an object experiences when it is launched vertically at a given velocity into the air and falls back to the ground? This question ignores air resistance.

When the object is launched into the air it has a kinetic energy proportional to its velocity squared. As it travels its energy is converted into gravitational potential energy as it slows down due to the ef...
AH
Answered by Andrew H. • Physics tutor
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