Effects of Heat

Q.

Is wood burning a physical or chemical change?

Q.

If the temperature between two bodies is same, heat transfer will happen between them.

1. False

2. True

Q.

What is the difference between ${\mathrm{C}}_{\mathrm{p}}$ and ${\mathrm{C}}_{\mathrm{v}}$ is equal to?

Q.

Among the following are physical or chemical changes.

Heating of an iron rod to red hot.

Q.

Heat always flows from:

1. Higher temperature to lower temperature.

2. Lower temperature to higher temperature.

3. Equal temperature.

4. None of these.

Q. Why does a hot cup of coffee kept open cool s after sometime

Q.

Why heat is not completely converted into work?

Q.

The boiling point of a liquid or condensation point of a gas have same numerical value.

1. False

2. True

Q.

Classify the following as chemical or physical changes: Cutting of trees.

Q.

At what temperature the density of water is maximum? State its value.

Q.

Two objects at the same temperature, one bigger than the other are placed in contact. Will heat be transfered from one object to another? Explain.

Q.

A block of ice

1. cannot radiate heat.

2. can radiate heat but cannot absorb heat.

3. can radiate aswell as absorb heat.

4. can absorb heat but cannot radiate heat.

Q.

Regulating body temperature is related to

1. high specific heat capacity of blood flowing

2. low specific heat capacity of water

3. high specific heat capacity of water

4. low specific heat capacity of blood flowing

Q. Gaps are left in between rails while laying a railway track. Why?

Q.

The wet clothes, when spread in the sunshine, dry rapidly because

1. both (a) and (b)

2. wind speed increases.

3. surface area increases

4. temperature increases

Q. State the different effects of heat on an object.

Q.

How are heat and temperature of a substance related to each other? [2 MARKS]

Q.

What is heat? State its SI unit.

Q.

Give an experiment to show that black surface is a better radiator of heat.

Q.

Two bodies are said to be in thermal ___when there is no transfer of heat taking place.

Q.

What affects the kinetic energy of a gas?

Q. LIQUID SOLUTIONS: The vapour pressure of a certain liquid is given by : log P = 3.54595 - 313.7/T + 1.40655log T, Where P is the vapour pressure in mm. T is Kelvin Temperature(log is of base 10) Determine the molar latent heat of vaporization as a function of temperature. Calculate its value at 80K.

Q.

(B) Classify the following as physical or chemical change.

12) Growing a tomato plant

Q.

Change in size of a substance when heat is taken away from it, is called _______

Q.

Differentiate between melting of wax and burning of a wax candle .

Q. What is solid state

Q.

State whether the following is true or false.

Heat is a form of energy that flows from a cold object to a hot object.

1. True
2. False

Q. Half life of a substance is 20 mnt.The time elapsed between 33% &67 % decay is:-

Q.

The density of a substance decreases when its temperature increases. Give reason.

Q. State whether true or false :
Heat is a form of energy which produces feeling of hotness.

1. True
2. False