83 free MCQs on Thermal Properties of Matter, each with its own worked answer and explanation. Temperature scales, thermal expansion, calorimetry, and the three modes of heat transfer including radiation laws.
Take the timed Thermal Properties of Matter chapterwise test →83 practice questions on Thermal Properties of Matter, sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Thermal Properties of Matter notes.
During a phase change (melting or boiling), temperature stays constant while heat is absorbed entirely as latent heat (Q=mL); temperature only rises again once the substance is fully in its new phase.
Q1.
Among these, the best conductor of heat is:
Q2.
A vacuum (Dewar) flask keeps its contents hot mainly by preventing heat loss through:
Q3.
Sea breeze and land breeze are examples of heat transfer by:
Q4.
Mercury is preferred in liquid thermometers mainly because:
Q5.
What is the value of absolute zero on the Celsius scale?
Q7.
The coefficient of area expansion (β) is related to the coefficient of linear expansion (α) by:
Q9.
Which mode of heat transfer can occur even through a vacuum?
Q10.
The latent heat of fusion of ice is the heat required to:
Q11.
According to the Stefan-Boltzmann law, the power radiated by a perfect black body is proportional to:
Q12.
Mayers relation for one mole of an ideal gas is:
Q13.
Newtons law of cooling is valid only when:
Q15.
According to Wiens displacement law, as the temperature of a black body increases, the wavelength of maximum emitted intensity:
Q16.
Heat transfer by the actual movement of heated fluid particles is called:
Q17.
Which of the following has the highest specific heat capacity among common substances?
Q18.
Heat flows spontaneously from a body at higher temperature to a body at:
Q19.
The SI unit of heat (a form of energy) is the:
Q20.
The SI unit of temperature is the:
Q21.
Most substances ___ when heated:
Q22.
Heat transfer through a solid without any bulk movement of the material is:
Q23.
Heat transfer by the actual movement of a heated fluid is called:
Q24.
The mode of heat transfer that requires no material medium is:
Q25.
A 200 g copper block (specific heat 400 J/kg·K) at 100 °C is dropped into 300 g of water (4200 J/kg·K) at 20 °C. The equilibrium temperature is about:
Q26.
A steel rod 2 m long (α = 1.2 × 10<sup>-5</sup> /°C) is heated through 100°C. Its increase in length is:
Q27.
A metal cube of volume 1000 cm<sup>3</sup> (α = 2 × 10<sup>-5</sup> /°C) is heated by 50°C. Its increase in volume is:
Q28.
Heat needed to convert 20 g of ice at -10°C to water at 0°C (c<sub>ice</sub> = 2.1 J/g°C, L<sub>f</sub> = 336 J/g) is:
Q29.
A copper rod of length 0.5 m and area 4 cm<sup>2</sup> (k = 400 W/mK) has a 100°C difference across its ends. The steady conduction rate is:
Q30.
A black body of area 1 cm<sup>2</sup> is at 1000 K (σ = 5.67 × 10<sup>-8</sup> W m<sup>-2</sup>K<sup>-4</sup>). The power it radiates is:
Q31.
A metal rod of length 1 m has a coefficient of linear expansion 2 × 10⁻⁵ /°C. If its temperature increases by 50°C, the increase in length is:
Q32.
500 g of water at 20°C is heated to 80°C. Taking specific heat of water as 4200 J/(kg·K), the heat required is:
Q33.
How much heat is needed to convert 10 g of ice at 0°C completely to water at 0°C? (Latent heat of fusion of ice = 334 J/g)
Q34.
Equal masses of two liquids A (specific heat 2000 J/kgK) and B (specific heat 4000 J/kgK) are mixed; A is at 80°C and B is at 20°C. What is the equilibrium temperature (assuming no heat loss)?
Q35.
A metal sphere cools from 80°C to 60°C in 5 minutes when the surrounding temperature is 20°C. By Newtons law of cooling, the initial excess temperature of the sphere over its surroundings is:
Q36.
A rod conducts heat at a steady rate of 20 W when the temperature difference across its ends is 10°C. If the temperature difference is increased to 25°C (all else unchanged), the new rate of heat conduction is:
Q37.
For a diatomic ideal gas, if Cv = (5/2)R, what is the value of Cp?
Q38.
Two rods of the same material and same length, but rod A has twice the cross-sectional area of rod B, conduct heat with the same temperature difference across their ends. The ratio of heat conducted per second by A to B is:
Q39.
A black body radiates energy at a rate E<sub>1</sub> at temperature T. If the temperature is doubled, the new rate of radiation E<sub>2</sub> in terms of E<sub>1</sub> is:
Q40.
A star has a surface temperature twice that of the Sun. According to Wiens law, the peak emission wavelength of the star compared to the Sun is:
Q41.
Steam at 100°C is passed into water to raise its temperature. The large heat released by steam is mainly due to:
Q42.
Why does a thick glass tumbler crack when very hot water is poured into it suddenly, but not when poured slowly?
Q43.
The heat needed to raise the temperature of 1 kg of a substance by 1 K is its:
Q44.
The heat needed to change the state of a substance at constant temperature is called the:
Q45.
Water has its maximum density at a temperature of:
Q46.
The coefficient of linear expansion has units of:
Q47.
The coefficient of volume expansion γ is related to the linear coefficient α by:
Q48.
By Newton’s law of cooling, the rate of heat loss of a body is proportional to its temperature difference with the:
Q49.
The peak wavelength of radiation from a hot body shifts to shorter wavelengths as its temperature rises. This is:
Q50.
A perfect black body is one that is a perfect:
Q51.
The Sun has a surface temperature near 5800 K and its emission peaks at 500 nm. A star whose emission peaks at 250 nm has a surface temperature of about:
Q52.
Two rods of equal length and area, conductivities 200 and 100 W/mK, are joined in series. The effective conductivity is:
Q53.
By Wien law (b = 2.9 × 10<sup>-3</sup> m K), a body at 2900 K emits maximum intensity at wavelength:
Q54.
5 g of steam at 100°C is passed into 100 g of water at 20°C (L<sub>v</sub> = 540 cal/g, c = 1 cal/g°C). The final temperature is about:
Q55.
A metal has volume expansion coefficient 5.4 × 10<sup>-5</sup> /°C. On heating by 100°C its density:
Q56.
A solid sphere and a hollow sphere of the same material, radius, and surface conditions are heated to the same temperature and allowed to cool in identical surroundings. Which cools faster initially, and why?
Q57.
A calorimeter of negligible heat capacity contains 200 g of water at 25°C. 50 g of ice at 0°C is added. Given latent heat of fusion = 336 J/g and specific heat of water = 4.2 J/(g·K), the final temperature of the mixture is approximately:
Q58.
A composite slab is made of two materials of equal thickness with thermal conductivities K1 and K2 placed in series (heat flows perpendicular to the layers). The effective thermal conductivity of the slab is:
Q59.
A liquid cools from 70°C to 60°C in 5 minutes and from 60°C to 50°C in 8 minutes, with the room temperature constant. Using Newtons law of cooling (approximate form), this tells us that:
Q60.
A gas undergoes a process where Cp/Cv = γ. If the gas is diatomic with vibrational modes also active at high temperature (f=7), the value of γ is:
Q61.
Two spheres of the same material, one of radius r and another of radius 2r, are heated to the same temperature and left to cool by radiation. The ratio of their rates of fall of temperature (dT/dt) initially, smaller to larger, is:
Q62.
A bimetallic strip used in a thermostat is made of two metals with different coefficients of linear expansion bonded together. When heated, the strip bends because:
Q63.
If the absolute temperature of a black body source is increased such that the total radiated power increases by a factor of 81, by what factor did the absolute temperature increase?
Q64.
For an ideal gas, the molar specific heat at constant volume for a monatomic gas is (3/2)R. If instead the gas were polyatomic (nonlinear, no vibration, f=6), the ratio of Cv(polyatomic) to Cv(monatomic) would be:
Q65.
A metal sphere of radius r is heated and then allowed to cool by radiation in surroundings at a fixed temperature, following Newton's law of cooling. If an identical sphere of twice the radius starts cooling from the same initial temperature in the same surroundings, which sphere's temperature drops faster initially, and why?
Q66.
By the Stefan–Boltzmann law, the energy radiated per unit area by a black body is proportional to T raised to the power:
Q67.
If the absolute temperature of a black body is doubled, the radiated energy increases by a factor of:
Q68.
In the conduction relation Q/t = kA(T₁ − T₂)/L, the constant k is the:
Q69.
During a phase change such as ice melting, the temperature of the substance:
Q70.
The latent heat of fusion of ice is approximately:
Q71.
Two rods of the same size but different conductivities are joined end to end. The pair conducts less heat than the better conductor alone because the poorer conductor:
Q72.
Wien’s displacement law can be written λ_max × T equals a:
Q73.
The net radiation loss of a body at temperature T is proportional to (T⁴ − T₀⁴), where T₀ is the temperature of the:
Q74.
Anomalous expansion means that between 0°C and 4°C, water actually:
Q75.
A good absorber of thermal radiation is also a good:
Q76.
Two rods of equal length and cross-section, of conductivities K₁ and K₂, are joined end to end. The effective thermal conductivity of the combination is:
Q77.
A body cools from 60°C to 50°C in 10 minutes in surroundings at 30°C. Using Newton law of cooling, its temperature after the next 10 minutes is approximately:
Q78.
A metal rod of length 1 m and expansion coefficient 2×10⁻⁵ per °C is heated by 100°C. Its increase in length is:
Q79.
The power radiated by a black body is proportional to the fourth power of its absolute temperature. If its temperature (in kelvin) is doubled, the radiated power becomes:
Q80.
Two stars have surface temperatures 6000 K and 12000 K. The ratio of the wavelengths at which they radiate maximum energy (6000 K : 12000 K) is:
Q81.
100 g of water at 20°C is mixed with 50 g of water at 80°C. The equilibrium temperature is:
Q82.
The heat required to melt 10 g of ice at 0°C (latent heat 80 cal/g) is:
Q83.
A bimetallic strip bends when heated primarily because the two metals have different:
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