Heat

Q. Define specific heat.

Q. A vessel contains a non linear triatomic gas .If 50%of gas dissociate into individual atoms then find new value of degree of freedom by ignoring the vibrational mode and any further dissociation.

Q.

A body of mass $20kg$ is moving with a velocity of $1\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$ Another body B of mass $1kg$ is moving wills a velocity of $20\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$. Find the ratio of kinetic energy of A and B

Q.

Himanshu has three buckets as shown below. He puts his right-hand in bucket A and left-hand in bucket B. He then puts both of his hands in normal water. His right-hand feels that the water here is hotter while his left-hand feels that the water here is colder.

What can you conclude from this?

1. Water in bucket A is hotter than water in bucket B
2. Water in bucket B is hotter than water in bucket A
3. Water in bucket A and B are equally hot
4. Water in bucket A and B are equally cold

Q.

What happens when a metal is heated?

1. Vibration of atoms increases.

2. Vibration of atoms decreases.

3. Vibration of atoms remains constant.

4. Vibration of atoms breaks the metal.

Q. The coefficient of linear expansion of silver is 18 ×10^-6 per °C. What do you understand by this

Q.

Hot: Oven:: Cold:?

1. Ice-cream

2. Air conditioner

3. Snow

4. Refrigerator

Q. What is the ratio of expansion coefficients?

1. 1 : 2 : 3
2. 1 : 3 : 2
3. 1 : 3 : 3
4. 3 : 2 : 1

Q. If a substance is hot, its particles will:

1. move faster than the cooler object
2. move slower than the cooler object
3. not move at all
4. moves with the same speed as that of the cooler object

Q. Heat can bring in:

1. change in temperature
2. change in state
3. chemical change
4. no change in volume

Q. When a body is heated, its average kinetic energy:

1. increases
2. remains same
3. becomes zero
4. decreases

Q.

Define the unit of heat and one calorie heat.

Q.

Define the term specific heat capacity and state its S.I. unit.

Q. In which direction does heat flow?

1. From a hot area to a cold area
2. From a cold area to a hot area
3. Heat does not flow
4. Heat flows in a random manner

Q. A vessel contains a non linear triatomic gas. If 50 percent of gas dissociated into individual atom then find the new degree of freedom by ignoring vibration mode and any further dissociation

Q.

$100g$ of ice at $-{10}^{\circ }C$ is heated on a gas stove till it forms water at ${80}^{\circ }C$. Calculate :

(a) Heat energy required to bring the ice to $0^{\circ }C$.

(b) The heat energy required to melt the ice

(c) Heat energy required to bring water to ${80}^{\circ }C$. [sp. heat capacity of ice $2J{g^{-1}}^{\circ }{C}^{-1}$; sp. heat capacity of water $4.2J{g}^{-1}{C}^{-1}$ and sp. latent heat of fusion of ice is $336J{g^{-1}}^{\circ }{C}^{-1}$.

Q. When radiated heat falls on an object, a part of it is reflected, a part of it is absorbed and a part may be transmitted. The temperature of the object increases due to the

जब एक वस्तु पर विकिरणित ऊष्मा आपतित होती है, तब इसका एक भाग परावर्तित होता है, एक भाग अवशोषित होता है तथा एक भाग पारगमित हो सकता है। वस्तु का ताप किसके कारण बढ़ता है?

1. Reflected part of the heat
   
   ऊष्मा के परावर्तित भाग
   
2. Absorbed part of the heat
   
   ऊष्मा के अवशोषित भाग
   
3. Transmitted part of the heat
   
   ऊष्मा के पारगमित भाग
4. There is no increase in temperature
   
   ताप में कोई वृद्धि नहीं होती है

Q. The quantity heat required to raise the temperature of unit mass of a substance 1 °C is

1. thermal energy
2. thermal/heat capacity
3. specific heat capacity
4. calorie

Q.

Two thin blankets layered together are warmer than one thick blanket.

Q. water at hundred degree Celsius has more heat than steam at hundred degree Celsius
Is it true or false?
Explain why

Q. This section contains 1 Assertion-Reason type question, which has 4 choices (a), (b), (c) and (d) out of which ONLY ONE is correct.

इस खण्ड में 1 कथन-कारण प्रकार का प्रश्न है, जिसमें 4 विकल्प (a), (b), (c) तथा (d) दिये गये हैं, जिनमें से केवल एक सही है।

A : Air around us exerts pressure.

A : हमारे आसपास की वायु दाब डालती है।

R : Air contracts on heating and expands on cooling.

R : वायु गर्म करने पर संकुचित होती है तथा ठण्डा करने पर प्रसारित होती है।

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
   
   (A) तथा (R) दोनों सही हैं तथा (R), (A) का सही स्पष्टीकरण है
2. Both (A) and (R) are true but (R) is not the correct explanation of (A)
   
   (A) तथा (R) दोनों सही हैं लेकिन (R), (A) का सही स्पष्टीकरण नहीं है
3. (A) is true but (R) is false
   
   (A) सही है लेकिन (R) गलत है
4. (A) is false but (R) is true
   
   (A) गलत है लेकिन (R) सही है

Q. Himanshu has three buckets, as shown below. He puts his right hand in bucket A and left hand in bucket B. He then puts both of his hands in normal water. His right hand feels that the water here is hotter, while his left hand feels that the water here is colder.

Q.

On heating the rod, the length of the rod increases. On what factors do the increase in length depends on?

1. The material of the rod

2. The length of the original rod

3. The increase in its temperature

4. All the above

Q. The amount of heat required to convert a unit mass of the substance from solid to liquid state at its melting point without any change in temperature is known as

1. Specific latent heat of fusion
2. Specific latent heat of vapourisation

3. Latent heat of fusion

4. Latent heat of vapourisation

Q. Atmospheric pressure in the center of a tropical cyclone is

1. very low because of rising warm air
2. very high because of converging winds.
3. very high because of sinking warm air
4. very low because of dense sinking air

Q. The speed of molecules ___.

1. in cold water is more than that of room temperature water
2. in hot water is more than that of room temperature water
3. in hot water is equal to that of room temperature water
4. in hot water is equal to that of cold water

Q. The amount of heat required to convert a unit mass of the substance from solid to liquid state at its melting point without any change in temperature is known as

1. Specific latent heat of fusion
2. Specific latent heat of vapourisation

3. Latent heat of fusion

4. Latent heat of vapourisation

Q. Sun produce heat and light by

1. inflamation
2. combustion
3. nuclear reaction
4. photo chemical reaction

Q. Define temperature.

Q.

explain thermal capacity and give its units.