Title 30 MAY PW PAPER (1).pdf ✅

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PHYSICS 1. A monoatomic gas of n-moles is heated from temperature T1 to T2 under two different conditions (i) at constant volume and (ii) at constant pressure. The change in internal energy of the gas is (A) More for (i) (B) More for (ii) (C) Same in both cases (D) Independent of number of moles 2. The temperature on Celsius scale is 25°C. What is the corresponding temperature on the Fahrenheit scale ? (A) 40°F (B) 77°F (C) 50°F (D) 45°F 3. A beaker is completely filled with water at 4°C. It will overflow if (A) Heated above 4°C (B) Cooled below 4°C (C) Both heated and cooled above and below 4°C respectively (D) None of the above 4. The total degree of freedom of a CO2 gas molecule is (A) 3 (B) 6 (C) 5 (D) 4 5. The P-V diagram of a gas system undergoing cyclic process is shown here. The work done during isobaric compression is 1 × 102 P(Nm–1) (A) 100 J (B) 200 J (C) 600 J (D) 400 J 6. On Celsius scale, temp. of a body increases by 30°C the increase in temperature on Fahrenheit scale (°F) will be :- (A) 50° (B) 40° (C) 30° (D) 54° 7. During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules, the work done during the process on the gas will be equal to (A) 1 J (B) –1 J (C) 2 J (D) –2 J 8. A cylindrical metal rod of length L0 is shaped into a ring with a small gap as shown. On heating the system (A) x decreases, r and d increase (B) x and r increase, d decreases (C) x, r and d all increase (D) Data insufficient to arrive at a conclusion 9. To increase the length of brass rod by 2% its temperature should increase by : (α = 0.00002°C–1 ) (A) 100°C (B) 1010°C (C) 1000°C (D) 800°C 10. The specific heat of a gas in an isothermal process is (A) Infinite (B) Zero (C) Negative (D) Remains constant 11. The ratio of mean kinetic energy per mole of hydrogen and oxygen at a given temperature is : (A) 1 : 16 (B) 1 : 8 (C) 1 : 4 (D) 1 : 1 12. A student takes 50gm wax (specific heat = 0.6 kcal/kg°C) and heats it till it boils. The graph between temperature and time is as follows. Heat supplied to the wax per minute and boiling point are respectively (A) 500 cal, 50°C (B) 1000 cal, 100°C (C) 1500 cal, 200°C (D) 1000 cal, 200°C PW-AITS_NT-04
13. In an isochoric process if T1 = 27°C and T2 = 127°C, then P1/P2 will be equal to (A) 9/59 (B) 2/3 (C) 3/4 (D) None of these 14. Two rods of same length and transfer a given amount of heat 12 second, when they are joined as shown in figure (i). But when they are joined as shown in figure (ii), then they will transfer same heat in same conditions in (A) 24 s (B) 13 s (C) 15 s (D) 48 s 15. What is number of degrees of freedom of an ideal diatomic molecule at ordinary temperature ? (A) 7 (B) 6 (C) 5 (D) 3 16. The ratio of the diameters of two metallic rods of the same material is 2 : 1 and their lengths are in the ratio 1 : 4. If the temperature difference between their ends are equal, the rate of flow of heat in them will be in the ratio (A) 2 : 1 (B) 4 : 1 (C) 8 : 1 (D) 16 : 1 17. Which of the following statements is/are false about mode of heat transfer ? (A) In radiation, heat is transferred from one medium to another without affecting the intervening medium (B) Radiation and convection are possible in vaccum while conduction requires material medium. (C) Conduction is possible in solids while convection occurs in liquids and gases. (D) All are correct 18. If the degree of freedom of a gas are f, then the ratio of two specific heats CP / CV is given by (A) 2 1 f  (B) 2 1 f  (C) 1 1 f  (D) 1 1 f  19. Star S1 emits maximum radiation of wavelength 420 nm and the star S2 emits maximum radiation of wavelength 560 nm, what is the ratio of the temperature of S1 and S2 (A) 4/3 (B) (4/3)1/4 (C) 3/4 (D) (3/4)1/2 20. The rate of emission of radiation of a black body at 273°C is E, then the rate of emission of radiation of this body at 0°C will be (A) 16 E (B) 4 E (C) 8 E (D) 0 21. A sphere, a cube and a disc all of the same material, quality and volume are heated to 600°C and left in air. Which of these will have the lowest rate of cooling ? (A) Sphere (B) Cube (C) Disc (D) All will have same rate 22. In kinetic theory of gases, it is assumed that molecules (A) have same mass but can have different volume (B) have same volume but mass can be different (C) have different mass as well as volume (D) have same mass but negligible volume 23. To double the volume of a given mass of an ideal gas at 27°C keeping the pressure constant, one must raise the temperature in degree centigrade to (A) 54° (B) 270° (C) 327° (D) 600° 24. At a certain temperature, the r.m.s. velocity for O2 is 400 m/sec. At the same temperature, the r.m.s. velocity for H2 molecules will be (A) 100 m/sec (B) 25 m/sec (C) 1600 m/sec (D) 6400 m/sec 25. Gas at a pressure P0 in contained in a vessel. If the masses of all the molecules are halved and their speeds are doubled, the resulting pressure P will be equal to (A) 4P0 (B) 2P0 (C) P0 (D) 0 2 P 26. Energy of all molecules of a monoatomic gas having a volume V and pressure P is 3 2 PV. The total translational kinetic energy of all molecules of a diatomic gas as the same volume and pressure is (A) 1 2 PV (B) 3 2 PV (C) 5 2 PV (D) 3 PV 27. On increasing number density for a gas in a vessel, mean free path of a gas : (A) Decreases (B) Increases (C) Remains same (D) Becomes double 28. The efficiency of Carnot’s engine operating between reservoirs, maintained at temperatures 27°C and –123°C is : (A) 50% (B) 24% (C) 0.75% (D) 0.4%