The temperature of an object is observed to rise in a period. In this period

(a) heat is certainly supplied to it

(b) heat is certainly not supplied to it

(c) heat may have been supplied to it

(d) work may have been done on it

Choose the correct option 

1.  (a) , (b) 

2. (b) , (c) 

3. (c) , (d) 

4. (a) , (d) 

Heat and work are equivalent. This means,

(a) when we supply heat to a body we do work on it

(b) when we do work on a body we supply heat to it

(c) the temperature of a body can be increased by doing work on it

(d) a body kept at rest may be set into motion along a line by supplying heat to it

Choose the correct option 

1.  (a) , (b) 

2. (b) , (c) 

3. (c) only

4. (a) , (d) 

The thermal conductivity of a rod depends on

1.  length

2.  mass

3.  area of cross section

4.  material of the rod.

In a room containing air, heat can go from one place to another:

A solid at temperature T₁, is kept in an evacuated chamber at temperature T₂ > T₁ . The rate of increase of temperature of the body is proportional to

1. T₂ – T₁

2.   \(T^2_2 -T^2_1\)n

3.   \(T^3_2 -T^3_1\)

4.   \(T^4_2 -T^4_1\)

The thermal radiation emitted by a body is proportional to Tⁿ where T is its absolute temperature. The value of n is exactly 4 for

1.  a blackbody

2.  all bodies

3.  bodies painted black only

4.  polished bodies only.

Two bodies A and B having equal surface areas are maintained at temperatures 10°C and 20°C. The thermal radiation emitted in a given time by A and B are in the ratio

1.   1 : 1.15

2.  1 : 2

3.   1 : 4

4.  1 : 16.

One end of a metal rod is kept in a furnace. In steady state, the temperature of the rod

1.  increases

2.  decreases

3.  remains constant

4.  is nonuniform

Newton’s law of cooling is a special case of

1.  Wien’s displacement law

2.  Kirchoff 's law

3.  Stefan’s law

4.  Planck’s law.

            
1. a

2. b

3. c

4. d