Question- At absolute zero
(a) all substances exist in solid form
(b) molecular motion ceases
(c) water becomes
(d) None of the above
Ans-(b)
Question- At critical temperature, the surface tension of a liquid is :
(a) zero
(b) infinity
(c) the same as that at any other temperature
(d) cannot be determined
Ans-(a)
Question- The reading of Centigrade thermometer coincides with that of Fahrenheit thermometer in a liquid. The temperature of the liquid is :
(a) –40°C
(b) 0°C
(c) 100°C
(d) 300°C
Ans- (a)
Question- Two metal rods A and B are having their initial length in the ratio 2 : 3 and the co-efficients of linear expansion in the ratio 3 : 4. When they are heated through the same temperature difference, the ratio of their line or expansion is
(a) 3 : 4
(b) 1 : 2
(c) 2 : 3
(d) 4 : 3
Ans-(b)
Question- As the temperature is increased, the time period of a pendulum :
(a) increases as its effective length increases even though its centre of mass still remains at the centre of the bob.
(b) decreases as its effective length increases even though its centre of mass still remains at the centre of the bob.
(c) increases as its effective length increases due to shifting of centre of mass below the centre of the bob.
(d) decreases as its effective length remains same but the centre of mass shifts above the centre of the bob.
Ans-(a)
Question- Which of the following qualities are best suited for a cooking utensil
(a) high specific heat and low thermal conductivity
(b) high specific heat and high thermal conductivity
(c) low specific heat and low thermal conductivity
(d) low specific heat and high thermal conductivity
Ans-(d)
Question- Relation between molar and principal specific heat of gases
(a) Cp = Mcp
(b) Cp = M + cp
(c) cp = MCp
(d) Cp = M – cp
Ans-(a)
Question- Liquids at temperature 60°C and 20°C, respectively, have mass ratio 3 : 4 and their specific heats in the ratio 4 : 5. If the two liquid mixed, the resultant temperature
(a) 70°C
(b) 0°C
(c) 35°C
(d) 40°C
Ans-(c)
Question- Dimensions of latent heat are
(a) [M1 L2 T–2]
(b) [M0 L2 T–2]
(c) [M1 L1 T–1]
(d) [M1 L1 T–2]
Ans-(b)
Question- A gas is compressed at a constant pressure of 50 N/m2 from a volume of 10m3 to a volume of 4 m3. Energy of 100 J is then added to the gas by heating. Its internal energy is:
(a) increased by 400 J
(b) increased by 200 J
(c) increased by 100 J
(d) decreased by 200 J
Ans-(a)
Question- A perfect gas is filled at same temperature in three containers of volumes V, V/2 and V/4. If the respective masses of the gas are M, M/2 and M/4, the pressures exerted on the walls of three containers are
(a) Unequal and maximum in the container of the smallest volume
(b) Unequal and maximum in the container of the largest volume
(c) Equal in all the three cases
(d) Equal in the two containers
Ans-(c)
Question- Peffect gas is one whose molecules
(a) Attract one another weakly
(b) Repel one another weakly
(c) Strongly attract or repel one another
(d) Neither attract or repel one another
Ans-(d)
Question- The internal energy of an ideal gas depends on :
(a) Pressure
(b) Volume
(c) Temperature
(d) Size of the molecule
Ans-(c)
Question- A given system undergoes a change in which work done by the system equals the decrease in its internal energy.The system must have undergone
(a) isothermal change
(b) adiabatic change
(c) isobaric change
(d) isochoric change
Ans-(b)
Question- Mean free path (λ) is
(a) inversely proportional to the diameter of molecule
(b) inversely proportional to the square of diameter of molecule
(c) inversely proportional to the number of molecules per unit volume.
(d) both b and c
Ans-(d)
Question- In a given process for an ideal gas, dW = 0 and dQ < 0.Then for the gas,
(a) temperature will decrease
(b) volume will increase
(c) pressure will remain constant
(d) temperature will increase
Ans-(a)
Question- If pressure and temperature of an ideal gas are doubled and volume is halved, the number of molecules of the gas
(a) become half
(b) become 4 times
(c) become two times
(d) remain constant
Ans-(a)
Question- Real gases obey gas laws more closely at
(a) High pressure and low temperature
(b) Low pressure and high temperature
(c) High pressure and high temperature
(d) Low pressure and low temperature
Ans-(b)
Question- By what percentage should the pressure of a given mass of a gas be increased so as to decrease its volume by 10% at a constant temperature?
(a) 8.1%
(b) 10.1%
(c) 9.1%
(d) 11.1%
Ans-(d)
Question- Two metal rods A and B of equal lengths and equal cross sectional areas are joined end-to-end. The co-efficients of thermal conductivity of A and B are in the ratio 2 : 3. When the free end of A is maintained at 100°C and the free end of B is maintained at 0°C, the temperature of the junction is
(a) 30°C
(b) 40°C
(c) 50°C
(d) 60°C
Ans-(b)
Question- In steady state
(a) temperature does not change with time
(b) all parts of the body are at same temperature
(c) there is no flow of heat
(d) all of the above
Ans-(a)
Question- A sphere, a cube and a thin circular plate, all of same material and same mass, are initially heated to same high temperature. Choose the correct statement.
(a) The plate will cool fastest and cube the slowest.
(b) The sphere will cool fastest and cube the slowest.
(c) The plate will cool fastest and sphere the slowest.
(d) The cube will cool fastest and plate the slowest.
Ans-(c)
Question- Velocity of heat radiation v as related to the velocity of light c is
(a) v > c
(b) v = c
(c) v < c
(d) no definite relation
Ans-(b)
Question- Heat is transferred most rapidly by the process of
(a) Conduction
(b) Convection
(c) Radiation
(d) Combustion
Ans-(c)
Question- A body cools from 50°C to 46°C in 5 minutes and to 40°C in the next 10 minutes. The surrounding temperature is :
(a) 30°C
(b) 28°C
(c) 36°C
(d) 32°C
Ans-(b)
Question- Newton’s law of cooling is used in laboratory for determining:
(a) Specific heat of gases
(b) Specific heat of liquids
(c) Latent heat of gases
(d) Latent heat of liquids
Ans-(b)
Question-If the rate of change of temperature is 0.2°C/ min and excess temperature of a body over surrounding is 20°C, the constant of proportionality is
(a) 0.1
(b) 0.01
(c) 1
(d) 0.001
Ans-(b)
Question-Newton’s law of cooling is applicable for
(a) Any excess of temperature over the surrounding
(b) Small excess of temperature over the surrounding
(c) Large excess of temperature over the surrounding
(d) Very large excess of temperature over the surrounding
Ans-(b)
Question-1 mole of a gas with γ = 7/5 is mixed with 1 mole of a gas with γ = 5/3, then the value of γ for the resulting mixture is
(a) 7/5
(b) 2/5
(c) 24/16
(d) 12/7
Ans-(c)
Question-At what temperature is the r.m.s. velocity of a hydrogen molecule equal to that of an oxygen molecule at 47°C ?
(a) 80 K
(b) –73 K
(c) 3K
(d) 20 K
Ans-(d)
Question-One mole of ideal monoatomic gas ( γ = 5/3) is mixed with one mole of diatomic gas ( γ = 7/5). What is γ for the mixture ? γ denotes the ratio of specific heat at constant pressure, to that at constant volume
(a) 3/2
(b) 23/15
(c) 35/23
(d) 4/3
Ans-(a)
Question-A gaseous mixture consists of 16 g of helium and 16 g of oxygen, The ratio CP/CV of the mixtrue is
(a) 1.4
(b) 1.54
(c) 1.59
(d) 1.62
Ans-(d)
Question-Even Carnot engine cannot give 100% efficiency because we cannot
(a) prevent radiation
(b) find ideal sources
(c) reach absolute zero temperature
(d) eliminate friction
Ans-(c)
Question-Which statement is incorrect ?
(a) all reversible cycles have same efficiency
(b) reversible cycle has more efficiency than the irreversible one
(c) Carnot cycle is a reversible one
(d) Carnot cycle has the maximum efficiency in all cycles
Ans-(a)
Question-Two spheres of the same material have radii 1 m and 4 m and temperatures 4000 K and 2000 K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is
(a) 1 : 1
(b) 16 : 1
(c) 4 : 1
(d) 1 : 9
Ans-(a)
Question-If mass-energy equivalence is taken into account, when water is cooled to form ice, the mass of water should
(a) increase
(b) remain unchanged
(c) decrease
(d) first increase then decrease
Ans-(c)
Question- Which of the following is more close to a black body ?
(b) Black board paint
(b) Green leaves
(c) Black holes
(d) Red roses
Ans-(c)
Question-Infrared radiations are detected by
(a) spectrometer
(b) pyrometer
(c) nanometer
(d) photometer
Ans-(b)
Question-Heat given to a body which raises its temperature by 1°C is
(a) water equivalent
(b) thermal capacity
(c) specific heat
(d) temperature gradient
Ans-(b)
Question-Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will
(a) increase
(b) decrease
(c) remain same
(d) decrease for some, while increase for others
Ans-(c)
Question- “Heat cannot by itself flow from a body at lower temperature to a body at higher temperature” is a statement or consequence of
(a) second law of thermodynamics
(b) conservation of momentum
(c) conservation of mass
(d) first law of thermodynamics
Ans-(a)
Question- Which of the following parameters does not characterize the thermodynamic state matter?
(a) temperature
(b) pressure
(c) work
(d) volume
Ans-(c)
Question- Which of the following statements is correct for any thermodynamic system ?
(a) The internal energy changes in all processes
(b) Internal energy and entropy are state functions
(c) The change in entropy can never be zero
(d) The work done in an adiabatic process is always zero
Ans-(b)
