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heater supplies 80 J of energy to a block of metal. The temperature of the block rises by 20 °C.
What happens to the block of metal when its temperature falls by 10°C?
Its internal energy increases by 40 J.
Its internal energy decreases by 40 J.
Its internal energy decreases by 160 J.
Its internal energy increases by 160 J.

Respuesta :

hamzaahmeds

Answer:

Its internal energy decreases by 40 J.

Explanation:

The energy supplied to the metal block causes the temperature of the block to rise. Therefore,

[tex]Heat\ Supplied = mC\Delta T\\80\ J = mC(20^oC)\\mC = 4\ J/^oC\\[/tex]

Now, we will use this value of mC to find out the energy change of block:

[tex]Energy\ Change = mC\Delta T\\Energy\ Change = (4\ J/^oC)(-10^oC)\\Energy\ Change = -40J\\[/tex]

It shows that when the temperature of the metal block falls by 10°C,

Its internal energy decreases by 40 J.

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