Explore topic-wise InterviewSolutions in .

i. medium

ii. speed

iii. fluid

iv. radiation

v. good conductors

B) liquid, 100° C

Absolute humidity.

Match the following :

(a) Liquids expand more than the solids. 

(b) Gases expand more than the liquids. 

(c) Heat transfer in solids is by conduction. 

(d) Heat transfer in liquids and gases is by convection. 

(e)Metals are conductors of heat. 

(f) Still air is an insulator of heat. 

(g) Black and dull surfaces are good absorbers of heat.

The correct option is D) Air pressure.

The correct option is B) ii only.

Water has the highest specific heat. So it takes lot of time to become hot. So it is used as coolant.

Dew: The water droplets condensed on the surface are known as dew.

Fog: Thick mist formed due to condensation of vapor on the dust particles.

The droplets keep floating in the air and form a thick mist which restricts visibility. This thick mist is called fog.

The water molecules present in vapour condense on the dust particles in air and form small droplets of water which form a thick mist called fog.

Fog is a cloud that touches the ground. Fog can be thin or thick, meaning people have difficulty seeing through it. In some conditions, fog can be so thick that it makes passing cars. Even monuments like London Bridge, in London, England, or the Golden Gate Bridge, in San Francisco, California, are almost impossible to see in thick fog.

Fog shows up when water vapor, or water in its gaseous form, condenses. During condensation, molecules of water vapor combine to make tiny liquid water droplets that hang in the air. You can see fog because of these tiny water droplets. Water vapor, a gas, is invisible.

At a particular temperature, a given volume of air can contain a certain maximum amount of water vapour. Normally, the temperature of air during the day is such that air is not saturated with water vapour present in it.

As the temperature falls, the capacity of air to hold water vapour becomes less. During a cold night, the temperature of air may fall to the dew point, or even below the dew point. If the temperature falls below the dew point, the excess of water vapour in air condenses on the surfaces of cold bodies and dew is formed. If the water vapour condenses on the fine dust particles present in the atmosphere, mist or fog is formed.

The variations of hotness, coldness can be termed as degree of hotness and coldness.

1) I am fine.

2) Yes, I know you. You are a thermometer.

3) Yes, I have seen in my home and hospital.

4) You are made of a narrow glass tube with thick walls which is closed at one end and You have a bulb of mercury or alcohol on the other end.

5) Mercury and alcohol have the best properties to measure temperature.

Yes, humidity is the other components of this kind.

1. Evaporation of sweat from our body makes us cool to maintain our body temperature.

2. In summer, the humidity of air is high. 

3. Due to high humidity and temperature, it becomes difficult to evaporate the sweat from our body to cool it down. 

4. But still our body losses water. 

5. High temperatures, along with humidity sometimes may cause heat stroke or sunstroke.

This water vapour present in the air is called humidity.

All the evaporated water from different water bodies go into air.

Aim : 

To show the evaporation of equal amounts of water in cap and dish. Apparatus : Cap, dish, water. 

Procedure : 

1. Take equal amounts of water in cap and dish. Keep them in open air for two hours. Now weigh the water in the cap and the dish. 

2. We can observe that the weight of water in dish is less than that of water in cap. 

3. This shows that the water in dish has more evaporation than the water in cap. 

4. It is due to more surface area of dish. 

5. As the surface area increases rate of evaporation also increases.

1. The blowing air increases the rate of evaporation. 

2. This is because any molecule escaping from the surface is blown away from the vicinity of the liquid. 

3. This increases the rate of evaporation.

4. This is the reason why the spirit in petri dish evaporates quickly when compared to that kept in closed room.

1. Some materials allow heat through them, this property is called conductivity. 

2. We use metals to make cooking vessels because they allow heat through them. 

3. We use material which do not allow heat to pass through as handles. 

4. So, cooking utensils made of metals while their handles are made of plastic or wood.

1. Due to higher specific heat of water oceans absorb the solar energy for maintaining a relatively constant temperature. 

2. Oceans absorb large amounts of heat at the equator. 

3. The oceans moderate the surrounding temperature near the equator. 

4. Ocean water transports the heat away from the equator to areas closer to the north and south pole.

5. This transported heat helps moderate the climate in parts of the Earth that are far from the equator. 

5. So higher specific heat of water is stabilising atmospheric temperature. 

6. So we have to extremely appreciate the role of higher specific heat of water to stabilise the atmospheric temperature.

The apparatus required is calorie meter, thermometer, stirrer, water, steam heater, wooden box, and aluminium shots.

Calorimeter, thermometer, stirrer, water, steam, heater, wooden box, and lead shots.

The rise in temperature depends on the nature of the material.

Vapour: The gaseous state of a substance is called vapor.

The specific heat of a material is the amount of heat required to raise the temperature of the unit mass of material by a unit.

B) temperature

1. Surface area 

2. temperature 

3. the amount of vapour already present in the surrounding air

The oceans behave like heat storehouses of earth.

During evaporation process, the energy of the molecules inside the liquid decreases and they slow down.

Watermelon brought out from the refrigerator retains its coolness for a longer time than any other fruit because of its large percentage of water.

The samosa seems to be cool outside but it is hot when we eat it because the curry inside the samosa contains ingredients with higher specific heat.

1. Temperature depends on nature of the material, hence the specific heat depends on its nature. 

2. If the specific heat, is high, the rise in temperature is low. [Q = mSΔt] 

3. It gives us an idea of degree of reluctance of a material to rise in temperature.

Principle of method of mixtures : 

Net heat lost by the hot body = Net heat gain by the cold body.

Net heat lost = Net heat gain.

This is known as the principle of the method of mixtures.

When two or more bodies are brought into thermal contact, then heat lost by hot body is equal to heat gain by cold body. Until they attain thermal equilibrium.

When two or more bodies at different temperatures are mixed with each other, then net heat lost by the hot bodies, is equal to net heat gained by the cold bodies until they attain thermal equilibrium or equal temperature.

Net heat lost = Net heat gained 

This is known as principle of method of mixtures.

To measure the temperature of a body with the help of a thermometer.

1. Gases have more higher energy than liquids and solids. 

2. When vapour condenses, it changes from gas to liquid. 

3. Therefore there is a drop in energy. 

4. This energy has to go (somewhere) to the surroundings. 

5. So surrounding air becomes warm when vapour phase of H₂O condenses.

Spirit absorbs heat energy from our palm and evaporates. So our palm becomes colder.

My opinion is that the temperature will not change. Approximately it will be 80°C only. Neela’s answer is wrong.

Beaker A and Beaker B has water at 80°C. So both beaker has 80°C temperature. Two beakers are in thermal equilibrium. So heat is not transfered to other objects.