1. A metal block is added to a pot of boiling water.Which of the following statements must be correct?
(1) The metal block and the water reach the same temperature finally
(2)The metal block gains energy from the boiling water.
(3)The change in internal energy of the metal block equals to that of water.
2. In an experiment to measure the energy released by some bread,pieces of bread are weighed and burnt using a Bunsen burner.The burning bread released heat to heat up a test tube of water.The temperature change of water is recorded .
Which of the following reasons explain(s) why the value found is greater than the true value ?
(1) The pieces of bread are incompletely burnt.
(2) Heat loss to surroundings .
(3) Heat released by the Bunsen Burner heats the water in the test tube.
Instructions:
1st statement: 2nd statement:
A. True True 2nd statement is a correct explanation of the 1 st statement
B. True true 2nd statement is not a correct explanation of the 1st statement
C. True False
D. False True
3(a)1st statement: When a piece of metal is heated ,its volume increases.
2nd statement: When a piece of metal is heated,the size of the molecules in it increases.
(b) 1st statement: If the average internal energy of molecules in object A is larger than of molecules in object B,then the temperature of A is higher than that of B.
2nd: The average internal energy of molecules is related to the temperature of the object.
Challenging Physics questions
2013-09-17 7:17 am
回答 (1)
2013-09-17 8:23 am
✔ 最佳答案
1. All 3 statements are correct.2. Statement (3) is correct.
Statements (1) and (2) are wrong, because when the piece of bread is incompletely burnt, or when there is heat loss to the surroundings, the actual heat absorbed by the water is smaller than it should be. Hence, the temperature rise of the water becomes lower. This gives a lower experimental value.
3. (a) Option C
2nd statement is wrong. When the metal is heated, the separation between molecules increases. The size of each molecule doesn't change.
(b) Option C.
2nd statement is wrong. Temperature is related to the average kinetic energy of molecules.
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