NCERT Class 11 MCQ Quiz Hub

MCQ Questions for Class 11 Physics sets 3

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1. Absorptive power of perfectly black body is




2. A black body at hot temperature at 227°C radiates heat at a rate of 5 cal/cm²s. at a temperature of 727°C the rate of heat radiated per unit area will be




3. 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




4. For which of the following process, the thermal conduction is maximum?




5. A bucket full of hot water is kept in a room and it cools from 75°C to 70°C in t1 minutes from 70°C to 65°C in t2 minutes and from 65°C to 60°C in t3 minutes; then




6. The good absorber of heat are




7. Two stars A and B radiate maximum energy at 3600°A and 3600°A respectively. Then the ratio of absolute temperatures of A and B is




8. A person with dark skin as compared to a person with white skin will experience




9. A cup of tea cools from 80°C to 60°C in one minute. The ambient temperature is 30°C. in cooling from 60°C to 50°C, it will take.




10. The best ideal black body is




11. The earth intercepts approximately one billionth of the power radiated by the sun. if the surface temperature of the sun were to drop by a factor of 2, the average radiant energy incident on earth per second would reduce by factor of




12. The process of heat transfer in which heat is transferred with actual migration of medium particles is known as (AFMC-94)




13. Unit of Stefans constant is given by




14. A metal piece heated to T1°K. The temperature of the surrounding is T2°K. the heat in the surrounding due to radiation is proportional to




15. The earth receives at its surface radiation from the sun at the rate of 1400 W/m². the distance of the centre of the sun from the surface of the earth is 1.5 1011 m and the radius of the sun is 7.0 108 m. treating sun as a black body, it follows from the above data that its surface temperature is,




16. A surface at temperature T0°K receives power P by radiation from a small sphere at temperature T >> T0 and at a distance d. if both T and d are doubled, the power received by surface will becomes approximately




17. The temperature of a piece of metal is raised from 27°C to 51.2°C. the rate at which metal radiates energy increases nearly




18. Emissivity of perfectly black body is




19. Co-efficient of reflection, coefficient of absorption and coefficient transmission are related as




20. Directions: The following question has four choices out of which ONLY ONE is correct. A thermodynamical system is changed from state (P1, V1) to (P², V²) by two different processes, the quantity which will remain same is:




21. The temperatures of inside and outside of a refrigerator are 273 K and 303 K respectively. Assuming, that the refrigerator cycle is reversible, for every joule of work done, the heat delivered to the surrounding will be nearly:




22. An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62°C, its efficiency is doubled. Temperature of the source is:




23. A black body at a temperature of 227°C radiates heat at the rate of 20 cal m-2s-1. When its temperature rises to 727°C, the heat radiated will be




24. Directions: The following question has four choices out of which ONLY ONE is correct. Which of the following is incorrect regarding the first law of thermodynamics? A. It is not applicable to any cyclic process B. It is a restatement of the principle of conservation of energy C. It introduces the concept of the internal energy D. It introduces the concept of the entropy




25. At a given volume and temperature, the pressure of a gas




26. Directions: The following question has four choices out of which ONLY ONE is correct. In a thermodynamic process, pressure of a fixed mass of the gas is changed in such a manner that the gas molecules give out 30 J of heat. Also, 10 J of work is done on the gas. If the internal energy of the gas was 40 J, what will be the final internal energy?




27. The translational kinetic energy of gas molecules at temperature T for one mole of a gas is




28. Which of the following parameters dose not characterize the thermodynamic state of matter?




29. Directions: The following question has four choices out of which ONLY ONE is correct. A Carnots engine works as a refrigerator between 250 K and 300 K. If it receives 750 calories of heat from the reservoir at the lower temperature, the amount of heat rejected at the higher temperature is __________.




30. A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased, so as to increase its efficiency by 50% of original efficiency?




31. For a diatomic gas change in internal energy for a unit change in temperature for constant pressure and constant volume is U1 and U2 respectively. What is the ratio of U1 and U2?




32. For a diatomic gas change in internal energy for a unit change in temperature for constant pressure and constant volume is U1 and U2 respectively. What is the ratio of U1 and U2?




33. Heat cannot by itself flow from a body at lower temperature to a body at higher temperature is a statement as a conseqence of




34. During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio Cp/Cv for the gas is




35. Real gases show mark able deviation from that of ideal gas behavior at




36. One mole of mono atomic gas (g = 5/3) is mixed with one mole of diatomic gas (g = 7/5) what will be the value of g for the mixture?




37. A room temperature the r.m.s. velocity of the molecules of a certain diatomic gas is found to be 1930 m/sec. the gas is




38. The temperature at which the r.m.s. velocity of H² becomes escape velocity from the earth is,




39. Moon has no atmosphere because




40. At a certain temperature, hydrogen molecules have r.m.s. velocity of 3 km/s. what is the r.m.s velocity of the oxygen molecules at the same temperature?




41. Latent heat of ice is




42. Energy supplied to convert unit mass of substance from solid to liquid state at its melting point is called




43. Which of the following is the unit of specific




44. An ideal gas is that which can




45. One mole of an ideal gas requires 207 J heat to raise the temperature by 10 K, when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by 10K, then heat required is




46. If 2 kcal, of heat is supplied to a system cause to change the internal energy of a gas is 5030 J, and external work done is 3350 J, then what is mechanical equivalent of heat?




47. For a gas, the r.m.s. speed at 800K is




48. The specific heat of a gas




49. Average kinetic energy of molecules is




50. The temperature of a gas is -68°C. to what temperature should it be heated, so that the r.m.s. velocity of the molecules be doubled?




51. Following gases are kept at the same temperature. Which gas possesses maximum r.m.s. speed?




52. According to kinetic theory of gases, at absolute zero of temperature




53. The average kinetic energy of the molecules of a gas at 27°C is 9 10-20 J. what is its average K.E. at 227°C?




54. In damped oscilation the directions of the restoring force and the resistive force




55. The displacement y of a particle executing periodic motion is given by y = 4 cos² (t/2) sin (1000t). This expression may be considered to be a result of superposition of the following number of harmonic motions




56. Spring is pulled down by 2 cm. What is amplitude of motion?




57. one of the two clocks on the earth is controlled by a pendulum and other by a spring. If both the clocks are taken to the moon, then which clock will have the same time – period of the earth?




58. When a particle performing uniform circular motion of radius 10 cm undergoes the SHM, what will be its amplitude?




59. For a magnet of time period T magnetic moment is M, if the magnetic moment becomes one fourth of the initial value, then the time period of oscillation becomes.




60. Time period of simple pendulum of length l and a place where acceleration due to gravity is g is T. what is the period of a simple pendulum of the same length at a place where the acceleration due to gravity is 1.029 is,




61. In the case of forced oscillations, which of the following statements is not true?




62. The motion of a particle executing simple harmonic motion is given by X = 0.01 sin 100p (t + 0.05), where X is in metres ant t in second. The time period in second is




63. In damped oscilation, the angular frequency of the oscillator




64. The acceleration of particle executing S.H.M. when it is at mean position is




65. In SHM, graph of which of the following is a straight line?




66. The period of thin magnet is 4 sec. if it is divided into two equal halves then the time period of each part will be




67. If the length of seconds pendulum is increased by 2%, how may seconds it will lose per day?




68. Length of a simple pendulum executing simple harmonic motion is increased by 21%. The percentage increase in the time – period of the pendulum of increased length is




69. If a simple harmonic oscillator has got a displacement of 0.02 m and acceleration equal to 2.0 ms-2 at any time, the angular frequency of the oscillator is equal to




70. The bob of a simple pendulum is a spherical hollow ball filled with water. A plugged hall near the bottom of the oscillating bob gets suddenly unplugged. During observation, till water is coming out, the time -period of the oscillation would




71. The maximum velocity for particle in SHM is 0.16 m/s and maximum acceleration is 0.64 m/s2. The amplitude is




72. The period of a simple harmonic oscillator is 2 sec. The ratio of its maximum velocity and maximum acceleration is




73. If a hole is bored along the diameter of the earth and a stone is dropped into the hole




74. A resonance air column of length 40 cm resonates with a tuning fork of frequency 450 Hz. Ignoring end correction, the velocity of sound in air will be




75. An observer is moving towards a stationary source of frequency 250 Hz with a velocity of 40 m/s. If the velocity of sound is 330 m/s, the apparent frequency heard by the observer will be




76. With the increase in temperature, the frequency of the sound from an organ pipe




77. Loudness of a note of sound is




78. The frequency of the note produced by plucking a given string increases as




79. A siren placed at a railway platfrom is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of velocity of train B to that of train A is




80. Energy is not carried by