Physics - Study Mode

[#756] A bimetal made copper and iron strips welded together is straight at room temperature. It is held vertically with iron strip towards left and copper strip towards right. If this bimetal is heated, it will
Correct Answer

(C) Bend towards left

Explanation

Solution: Since the strips are welded together, the combined strip will bend towards left ( towards iron ) since copper strip will have more length than the iron strip.

[#757] Thermal expansion of materials arises from
Correct Answer

(D) Asymmetry of potential energy curve

Explanation

Solution: Thermal expansion of materials arises from asymmetry of potential energy curve.

[#758] When a ring of metal is heated what happens to its hole ?
Correct Answer

(A) Expands

Explanation

Solution: The hole size will increase because in expansion the size between two molecules do not increase so when the molecules on the outer edge move outward. Due to expansion, the size of the hole will also increase so as to compensate the distance change between the molecules.

[#759] The earth is a
Correct Answer

(C) Good absorber and good radiator of heat

Explanation

Solution: The earth is a good absorber and good radiator of heat.

[#760] When temperature difference between liquid and its surroundings is doubled, the rate of loss of heat will:
Correct Answer

(B) Double

Explanation

Solution: According to Newton’s law of cooling, the rate of loss of heat of a body is directly proportional to the difference between the temperature of hot body and temperature of the surroundings, provided that the difference in temperature is small enough.