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physics related question.

Hello to everyone.I am struggling with one of my physics multiple choice question.The question is :
A block of copper and a block of lead are heated. The internal energy of each block increases by
the same amount.
The block of copper has a lower thermal capacity than the block of lead.
Which conclusion can be made from this information?
options:
A The temperature increase of the copper is greater than the temperature increase of the lead.
B The temperature increase of the copper is the same as the temperature increase of the lead.
C The temperature increase of the copper is less than the temperature increase of the lead.
D The melting point of copper is lower than the melting point of lead.
Can anyone help me out with this one and kindly explain as well.
Thanks.

Reply 1

username3249896

H_{Cu} = C_{Cu} \Delta T

H_{Pb} = C_{Pb} \Delta T

The rise in temperature is inversely proportional to the heat capacity for the same heat energy supplied

Reply 2

abdullahAK

physics question.
can anyone help me out with this question above.
why the doesn't momentum changes ?

(edited 5 years ago)

Reply 3

username3249896

Original post by abdullahAK

physics question.
can anyone help me out with this question above.

The speed is the same
So the kinetic energy is the same

The direction of motion changes
The velocity changes
So the momentum is different

Reply 4

abdullahAK

so the momentum is same but the direction is different.
Am I right?

Reply 5

username3249896

Original post by abdullahAK

so the momentum is same but the direction is different.
Am I right?

No
Momentum is different

Momentum = mass x velocity
direction of motion changes
so velocity changes
hence momentum changes

Momentum has same magnitude but opposite direction
so momentum is different

Reply 6

abdullahAK

Ahhhh,Okay.
thank you, you've really helped me a lot.

Reply 7

abdullahAK

Bobb jo,I want to ask that what is meant by internal energy.

Reply 8

username3249896

Original post by abdullahAK

Bobb jo,I want to ask that what is meant by internal energy.

Internal energy is the sum of a random distribution of kinetic energies and potential energies associated with the molecules of a system.

Reply 9

abdullahAK

previous question which I asked to you about lead and copper.
My question is: When both of them internal energy increased by same amount why didn't their temperature were same.?

Reply 10

username3249896

Original post by abdullahAK

previous question which I asked to you about lead and copper.
My question is: When both of them internal energy increased by same amount why didn't their temperature were same.?

\Delta U = q + w

The increase in internal energy is equal to sum of the heat supplied to the system and the work done on the system. The work done here is 0 since there is no change in volume. So the increase in internal energy is equal to the heat supplied.

The heat supplied is the same. The heat supplied E is related to the rise in temperature by the following

E = C \Delta \theta

The heat supplied is the same. So

\Delta \theta = \dfrac{E}{C}

the rise in temperature is inversely proportional to the heat capacity
the one having a higher heat capacity will have its temperature rise by a smaller amount
So copper will have higher temperature rise.

We only have the information about the temperature rise. The final temperature can be the same if they are at appropriate initial temperatures.