Thermodynamics PYQs Set 8 (PDF)

Set 8 of 16 · Questions 211-240 of 459

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Mere Teacher · Previous Year Questions NEET Physics · Thermodynamics · Set 8 (Q211-240)
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211. $1 kg of steam at 150^{\circ} C is passed from a steam chamber is to a copper coil immersed in 20 L of water. The steam condenses in the coil and is returned to the steam chamber as water at 90^{\circ} C . Latent heat of steam is 540 cal g^{- 1}, specific heat of the steam is 1 cal g^{- 10} C^{- 1} . Then, the rise in temperature of water is$ (1) $75^{\circ} C$ (2) $60^{\circ} C$ (3) $30^{\circ} C$ (4) $20^{\circ} C$ 212. $A Carnot’s cycle operating between T_{1} = 600 K and T_{2} = 300 K producing 1.5 kJ of mechanical work per cycle. The heat transferred to the engine by the reservoirs$ (1) $2.5 kJ$ (2) $3 kJ$ (3) $3.5 kJ$ (4) $4 kJ$ 213. $A Carnot engine working between 300 K and 600K has work output of 800 J per cycle. What is amount of heat energy supplied to the engine from source per cycle$ (1) $1800 J/cycle$ (2) $1000 J/cycle$ (3) $2000 J/cycle$ (4) $1600 J/cycle$ 214. $The heat energy required convert 10 kg of ice at - 10^{\circ} C into water at 0^{\circ} C is (specific heat capacity of ice = 0.5 cal g^{- 1} and latent heat of fusion of ice = 80 cal g^{- 1})$ (1) $357 \times 10^{4} J$ (2) $357 \times 10^{3} J$ (3) $357 \times 10^{2} J$ (4) $357 \times 10^{5} J$ 215. $A vessel that can withstand a pressure of 100 atm is filled with hydrogen at 27^{\circ} C up to a pressure of 20 atm . If the vessel is heated, then the temperature at which it explodes is$ (1) $500 K$ (2) $1000 K$ (3) $1500 K$ (4) $2000 K$ 216. $A gas at N.T.P. is suddenly compressed to one-fourth of its original volume. If γ = 1.5, then the final pressure is$ (1) $4 times$ (2) $1.5 times$ (3) $8 times$ (4) $\frac{1}{4} times$ 217. $Isothermal bulk modulus of a gas at a pressure P is (γ -ratio of specific heat capacities of the gas)$ (1) $γ$ (2) $γP$ (3) $P$ (4) $\frac{γ}{P}$ 218. $In which of the processes, does the internal energy of the system remain constant?$ (1) $Isobaric$ (2) $Isothermal$ (3) $Adiabatic$ (4) $Isochoric$ 219. $A monatomic gas of volume ' V' and pressure ' P' expands isothermally to a volume ' 27 V' and then compressed adiabatically to a volume ' V'. The final pressure of the gas is$ (1) $3 P$ (2) $2 P$ (3) $9 P$ (4) $4 P$ 220. $A cylinder of fixed capacity of 44.8 liters contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by 20.0°C will be: (Given gas constant R = 8.3 J K^{- 1} m o l^{- 1})$ (1) $249J$ (2) $415J$ (3) $498J$ (4) $830J$ 221. $Heat energy of 735 J is given to a diatomic gas allowing the gas to expand at constant pressure. Each gas molecule rotates around an internal axis but do not oscillate. The increase in the internal energy of the gas will be:$ (1) $525J$ (2) $441J$ (3) $572 J$ (4) $735 J$ 222. $The thermodynamic process, in which internal energy of the system remains constant is$ (1) $Isochoric$ (2) $Adiabatic$ (3) $Isothermal$ (4) $Isobaric$ 223. $In an adiabatic expansion of an ideal gas the product of pressure and volume$ (1) $remains constant$ (2) $at first increases and then decreases$ (3) $decreases$ (4) $increases.$ 224. $A slab of stone of area 3600 cm^{2} and thickness 10 cm is exposed on the lower surface to steam at 100^{\circ} C . A block of ice at 0^{\circ} C rests on upper surface of the slab. In one hour 4.8 kg of ice is melted. The tiermal conductivity of the stone in Js^{- 1} m^{- 1} k^{- 1} is (Latent heat of ice = 3.36 \times 10^{5} J / kg)$ (1) $12.0$ (2) $10.5$ (3) $1.02$ (4) $1.24$ 225. $On a new temperature scale, the melting point of ice is 20^{\circ} X and the boiling point of water is 110^{\circ} X . A temperature of 40^{\circ} C would be indicated on this new temperature scale as$ (1) $60^{\circ} X$ (2) $56^{\circ} X$ (3) $70^{\circ} X$ (4) $54^{\circ} X$ 226. $A gas is compressed from a volume of 2 m^{3} to a volume of 1 m^{3} at a constant pressure of 100 Nm^{- 2} . Then it is heated at constant volume by supplying 150 J of energy. As a result, the internal energy of the gas$ (1) $increases by 250 J$ (2) $decreases by 250 J$ (3) $decreases by 50 J$ (4) $increases by 50 J$ 227. $The efficiency of a heat engine is ' η' and the coefficient of performance of a refrigerator is ' β'. Then$ (1) $η = \frac{1}{β}$ (2) $η = \frac{1}{β + 1}$ (3) $η β = \frac{1}{2}$ (4) $η = \frac{1}{β - 1}$ 228. $If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cycle process, then$ (1) $E = 0$ (2) $Q = 0$ (3) $W = 0$ (4) $Q = W = 0$ 229. $A steel ball of mass 200 g falls freely from a height of 20 m and bounces to a height of 10.8 m from the ground. If the energy lost in this process is absorbed by the ball, the rise in its temperature is (g = 10 ms^{- 2}), specific heat capacity of steel is 460 Jkg^{- 1} K^{- 1})$ (1) $0.1^{\circ} C$ (2) $1^{\circ} C$ (3) $0.2^{\circ} C$ (4) $2^{\circ} C$ 230. $A refrigerator works between 4^{o} C and 3 0^{o} C . It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is (Take 1 cal = 4.2 Joules)$ (1) $236.5 W$ (2) $2365 W$ (3) $2.365 W$ (4) $23.65 W$ 231. $A heating element of mass 100 g and having specific heat of 1 J / (g^{\circ} C) is exposed to surrounding air at 27^{\circ} C . The element attains a steady state temperature of 127^{\circ} C while absorbing 100 W of electric power. if the power is switched Off, then approximate time taken by the element to cool down to 126^{\circ} C will be (neglect radiation)$ (1) $0.1 s$ (2) $1.0 s$ (3) $5.0 s$ (4) $10.0 s$ 232. $1g of a liquid is converted to vapour at 3 x 1 0^{5} Pa pressure. If 10% of the heat supplied is used for increasing the volume by 1600 c m^{3} during this phase change, then the increase in internal energy in the process will be:$ (1) $4320J$ (2) $432000 J$ (3) $4800 J$ (4) $4.32 x 1 0^{8} J$ 233. $The door of an operating refrigerator is kept open. As a result, the temperature of the room will$ (1) $remain unchanged$ (2) $increases$ (3) $decreases$ (4) $depends on the contents inside the refrigerator$ 234. $If the door of a refrigerator is kept open then which of the following is ture$ (1) $Room is cooled$ (2) $Room is heated$ (3) $Room is either cooled or heated$ (4) $Room is neither cooled nor heated$ 235. $The area of a circular copper coin increases by 0.4 % when its temperature is raised by 100^{\circ} C . The coefficient of linear expansion of the coin is:$ (1) $1 \times 10^{- 5} /° C$ (2) $2 \times 10^{- 5} /° C$ (3) $3 \times 10^{- 5} /° C$ (4) $4 \times 10^{- 5} /° C$ 236. $An ideal gas heat engine operates in a Carnot's cycle between 22 7^{o} C and 12 7^{o} C . It absorbs 6 \times 104 J at high temperature. The amount of heat converted into work is ....$ (1) $4.8 \times 1 0^{4} J$ (2) $3.5 \times 1 0^{4} J$ (3) $1.6 \times 1 0^{4} J$ (4) $1.2 \times 1 0^{4} J$ 237. $A thermodynamic process of uncontrolled change satisfying the equation Q = W = 0, is [Q = heat supplied, W = work done]$ (1) $cyclic$ (2) $isothermal$ (3) $isochroic$ (4) $free expansion$ 238. $When 50 g of water at 10^{\circ} C is mixed with 50 g of water at 100^{\circ} C . The resultant temperature is$ (1) $80^{\circ} C$ (2) $55^{\circ} C$ (3) $2.5^{\circ} C$ (4) $45^{\circ} C$ 239. $We consider a thermodynamic system. If Δ U represents the increase in its internal energy and W the work done by the system, which of the following statements is true?$ (1) $Δ U = - W in an isothermal process$ (2) $Δ U = W in an isothermal process$ (3) $Δ U = - W in an adiabatic process$ (4) $Δ U = W in an adiabatic process$ 240. $In a cyclic process, work done by the system is$ (1) $Zero$ (2) $Equal to heat given to the system$ (3) $More than the heat given to system$ (4) $Independent of heat given to the system$