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The process of transfer of heat from hotter to colder end through the conductor is called conduction. This mode transfer of heat happens more in solid conductors.

Mercury is a metal found in liquid state. It expands more and uniformly over a wide range of temperature. So mercury is used as thermometric liquid.

Correct Answer is: (c, d)

v_rms = √(3RT/M) Bar v = √(8RT/πM) = √(2.55 RT/M) v_p = √(2RT/M).

Correct Answer is: (c) p/n

Vpⁿ = (V + ΔV) (p + Δp)ⁿ = Vpⁿ (1 + ΔV/V) (1 + n. ΔP/P)

or ΔV V = -n. Δp/p

Now, k = - Δp/(ΔV/V) = p/n.

Correct Answer is: (c) 3m_A = 2m_B 

Let p_A, p_B be the initial pressures in A and B respectively. When the gases double their volumes at constant temperature, their pressures fall to P_A/2 and P_B/2

∴ for A, p_A - p_A/2 = Δp

or p_A = 2Δp

for B, p_B - p_B/2 = 1.5Δp

or p_B = 3Δp

∴ p_A/p_B = 3/2.

Also, p_AV = m_A/M RT and p_BV = m_B/M RT.

∴ p_A/p_B = m_A/m_B

∴ m_A/m_B = 2/3 or 3m_A = 2m_B.

The reason is that after the hail-storm, the ice absorbs the heat energy required for melting from the surroundings, so the temperature of the surroundings falls further down and we feel more cold.

Correct Answer is: (b)

pV = nRT  or p = (nR/V) T

For a p–T graph, slope = nR/V ∝ 1/V.

Correct Answer is: (a, b, c, & d)

Correct Answer is: (d) may have any value between -∞ and -∞

 The molar heat capacity has the general definition

C = 1/n . ΔQ/ΔT ,

where n = number of moles, ΔQ = heat absorbed by the gas and ΔT = rise in temperature of gas.

It is possible to obtain almost any set of values for ΔQ and ΔT by proper selection of a process.

1. A steam bum is more damaging as when steam hits our skin it condenses to water and attains the temperature of our skin. There will be an energy release due to latent heat and fall in temperature. Whereas when boiling water fall on our skin, there is no transition in energy, only fall in temperature and heat transferred to the skin will be due to cooling.

2. igloo is built as a winter shelter due to snow’s insulating property. The inside of an igloo acts as an insulator and keeps it relatively warm. 

3. During summer, heat causes expansion in tracks that are made of metal. If gaps a re not left between tracks, the track may bend due to expansion and accidents can occur. 

4. As hot gases and smoke are lighter, they rise up. Therefore chimneys are placed high up in kitchens and factories, so that the hot air can rise up and go out into the atmosphere. 

5. We wear woollen clothes in winter, as wool acts as an insulator. The air trapped between the woollen sweater and our clothes acts as an insulator and does not allow air from outside to enter, thereby keeping us warm.

• Specific latent heat is the amount of heat energy absorbed or liberated by unit mass of a substance during change of state without causing any change in temperature. 
• Specific latent heat is given as L = Q/m, where ‘Q’ is the amount of heat energy absorbed or liberated and ‘m’ is mass of a substance during its change of phase at a constant temperature. 
• The SI unit of specific latent heat is J/kg.

Correct answer is (c) Rod-1

Ice is kept in a double-walled container so as to prevent melting of ice from the heat absorbed present in the immediate surroundings. The vacuum present in between the two walls prevents the transfer of heat from the first to the second wall and hence the ice remains in the solid form for a longer time period.

• The specific heat capacity of a substance is defined as the amount of heat required to raise the temperature of 1 kg of the substance by 1°C or 1 K. 
• Q = mC∆T, where Q is the quantity of heat required to raise the temperature and m is the mass of the body and AT is the change in temperature of the body.
• The SI unit of specific heat capacity is Jkg^-1 K^-1 . The most commonly used units of specific heat capacity are J/kg°C and J/g°C.

Correct answer is (b) Conduction

An earthen pot consists of small pores from which the water inside the pot constantly seeps out and gets evaporated due to the presence of high temperature around it. The evaporation process requires heat which is acquired from the surface of the pot, hence making the water and the pot cooler.

1. (a) Heat 

2. (d) kelvin 

3. (c) Rod-1 

4. (b) Conduction 

5. (d) Thermos flask

1. No. The molecules in a solid are only free to vibrate about their fixed positions.

2. For convection to take place, the molecules need to move carrying the heat with them. 

3. Hence convection cannot take place in solids.

Air, milk, steel.

1. Heat energy from the Sun reaches the Earth by radiation. 

2. While standing near fire we feel the heat which is transferred as radiation.

3. Black surfaces absorb heat radiation. So that the bottom of the cooking vessels are painted black. 

4. White color reflects heat radiation. That’s why we are advised to wear white cloth during summer.

(c) The assertion is true, but the reason is false.

Black surfaces absorb heat radiation. White color reflects heat radiation.

The form of heat transfer from places of high temperature to places of low temperature by the actual movement of molecules is called convection. Convection takes place in liquids and gases.

(c) Richter scale

(b) radiation

(d) liquids and gases

(a) Both assertion and reason are true and the reason is the correct explanation of the assertion.

1. Expansion 

2. Increase in temperature 

3. Change in state

1. b 

2. d 

3. a

4. c

(c) freezing

1. e 

2. a 

3. d 

4. c 

5. b

(b) Both assertion and reason are true, but reason is not the correct explanation of the assertion.

(d) All of them

1. radiation 

2. morel 

3. water 

4. Water 

5. electro magnetic waves 

6.  \(\frac{Q}{\Delta T}\)

7. 4.186 J

8. \(\frac{Q}{mx \Delta T}\)

1. c 

2. d 

3. a 

4. b

1. c 

2. d 

3. b 

4. a

1. Mass and materials of the bodies in contact. 

2. Difference in their temperatures.