Dr. Ch.Ramakrishna
Dr.R.K's Frames of Physics
 Hyderabad
 
 
 THERMODYNAMICS & ELECTROSTATICS
 
 
 1.    One kg of ice at 0°C is mixed with 1 kg of water at 80°C. The resulting temperature will be?
     1) between 0°C and 80°C
     2) 0°C
     3) less than 0°C
     4) greater than 0°C
 
 2.    Boiling water is changing into steam. Under this condition, the specific heat of water is?
     1) one    2) zero
     3) ¥        4) < 1
 
 3.    10g of ice at –20°C is dropped into a calorimeter containing 10g of water at 10°C. The specific heat of water is twice that of ice. When equilibrium is reached, the calorimeter will contain?
     1) 10 g ice and 10 g water
     2) 20 g water
     3) 5 g ice and 15 g water
     4) 20 g ice
 
 4.    The ratio of the densities of the two bodies is 3 : 4 and specific heat in the ratio 4 : 3. The ratio of their thermal capacities for unit volume is?
     1) 9 : 16    2) 2 : 1
     3) 16 : 9    4) 1 : 1
 
 5.    Steam is passed into 22 g of water at 20°C. The mass of water that will be present when the water acquires a temperature of 90°C (Latent heat of stream is 540 cal/g) is?
     1) 24.8 g    2) 24 g
     3) 36.6 g    4) 30.0 g
 
 6.    A piece of metal at 850 K is dropped into 1 kg water at 300 K. If the equilibrium temperature of water is 350 K, then the heat capacity of the metal, expressed in JK–1, is?
     1) 420    2) 240
     3) 100    4) 24
 
 7.    Work done by 0.1 mole of a gas at 27°C to double its volume at constant pressure is (R = 2cal mol–1K–1)?
     1) 54 cal    2) 600 cal
     3) 60 cal    4) 546 cal
 
 8.    A gas at NTP is suddenly compressed to one fourth of its original volume. If g is supposed to be (3/2), then the final pressure is?
     1) 4 atmospheres
     2) (3/2) atmospheres
     3) 8 atmospheres
     4) (1/4) atmospheres
 
 9.    The molar heat capacity in a process of a diatomic gas if it does a work of Q/4 when a heat of Q is supplied to it is?
     1) 2/5 R    2) 5/2 R
     3) 10/3 R    4) 6/7 R
 
 10.    When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy is?
     1) 2/5        2) 3/5
     3) 3/7        4) 5/7
 
 11.    If the amount of heat given to a system be 35 Joule and the amount of work done by the system be –15 Joule then the change in the internal energy of the system is?
     1) –50 Joule    2) 20 Joule
     3) 30 Joule    4) 50 Joule
 
 12.    The latent heat of vaporization of water is 538 cal/g. If the work done in the process of evaporation of 1 g water is 168 J, the increase in internal energy is?
     1) 240 cal    2) 498 cal
     3) 370 cal    4) 706 cal
 
 13.    If one mole of a monoatomic gas (g = 5/3) is mixed with one mole of a diatomic gas (g = 7/5). The value of g for the mixture is?
     1) 1.40    2) 1.50
     3) 1.53    4) 3.07
 
 14.    An ideal gas at 27°C is compressed adiabatically to 8/27 of its original volume [TVg–1 = constant and g = 5/3]. Then the rise in temperature is?
     1) 450°C    2) 375°C
     3) 225°C    4) 400°C
 
 15.    In an adiabatic change, the pressure P and temperature T of a monoatomic gas are related by the relation P µ TC where 'C' equals?
     1) 5/3        2) 2/5
     3) 3/5        4) 5/2
 
 16.    A •made of lead moving with velocity v, hits a wall. Its 50% kinetic energy is converted into heat, then increase in temperature will be?
 
     1)     2)
     3)     4)
 
 17.    The height of a waterfall is 84 metre. Assuming that the entire kinetic energy of a falling water is converted into heat, the rise in temperature of the water will be?
     1) 0.196°C    2) 1.960°C
     3) 0.96°C    4) 19.6°C
 
 18.    Two liquids at temperature 60°C and 20°C respectively have masses in the ratio 3 : 4 and their specific heats in the ratio 4 : 5. If the two liquids are mixed, the resultant temperature is?
     1) 70°C    2) 50°C
     3) 40°C    4) 35°C
 
 19.    The internal energy of a given mass of an ideal gas depends on its?
     1) pressure    2) temperature
     3) volume    4) density
 
 20.    A metal sphere of radius 'r' and specific heat s is rotated about an axis passing through its center at a speed of n rotations per second. It is stopped and 50% of its energy is used in increasing its temperature, then the rise in temperature of the sphere is?
 
     1)     2)
     3)     4)
 
 21.    [A]: It is possible to transfer heat energy from body at lower temperature to body at higher temperature by using external agency.
     [R]: External agency extracts large heat from colder body by doing work rejects smaller heat to hotter body, hence heat transfer is possible.
     1)    Both A and R are true and R is the correct explanation of A
     2)    Both A and R are true but R is not the correct explanation of A
     3)    A is true but R is false
     4)    A is false but R is true
 
 22.    Two samples A and B, of a gas at the same initial temperature and pressure are compressed from volume V to V/2, A isothermally and B adiabatically. The final pressure of A will be?
     1) greater than that of B
     2) equal to that of B
     3) less than that of B
     4) twice that of B
 
 23.    [A]: No two electric lines of force can intersect each other.
     [R]: Tangent at any point of electric line force gives the direction of electric field.
     1)    Both A and R are true and R is correct explanation for A
     2)    Both A and R are true and R is not correct explanation for A
     3)    A is true but R is false
     4)    A is false but R is true
 
 24.    A positive point charge 50 mC is located in the x-y plane whose
 
     position vector is  The strength of electric field at a point whose position vector is
      is
     1) 900 N/C    
     2) 500 N/C
     3) 4000 N/C    4) 4500 N/C
 
 25.    Four charges 1 nC, 2 nC, 1 nC and 2 nC are placed respectively at the corners of a square of side 2 m. The force experienced by a charge 1 × 10–9 C when placed at the point of intersection of the diagonals is
     1) Zero
     2) 18 × 10–9 N
     3) 9Ö2 × 10–9 N
     4) 9 × 10–9 N
 
 26.    A charge q is placed at the centre of the line joining of two equal charges Q each. The system of three charges will be in equilibrium if q is equal to
     1) –Q/2    2) +Q/2
     3) –Q/4    4) –4Q
 
 27.    Two point charges placed at a certain distance r in air exert a force of  F on each other. Then the distance r1 at which these charges will experience the same force in a medium of dielectric constant K is?
     1) r        2) r/K
     3) r/ÖK    4) rÖK
 
 28.    An oil drop carrying a charge of 2 electrons has a mass of 3.2 × 10–17 kg. It is falling freely in air with terminal speed. The electric field required to make the drop move upwards with the same speed is (g = 10 ms–2)?
     1) 2 × 103 V m–1
     2) 1 × 103 V m–1
     3) 3 × 103 V m–1
     4) 8 × 103 V m–1
 
 29.    Two point charges of +3 coulomb and +9 coulomb repel each other with a force of 27 newton. Charges of –3 coulomb are given to each of these charges, then the force of attraction is?
     1) 27 newton    
     2) 18 newton
     3) 9 newton    4) zero
 
 30.    Two electrons separated by distance 'r' experience a force 'F' between them. The force between a proton and a singly ionized helium atom separated by distance 2r is?
     1) 4F        2) 2F
     3) F/2    4) F/4
 
 31.    Electric charges of 1 mC, –1mC and 2 mC are placed in air at the corners A, B and C respectively of an equilateral triangle ABC having length of each side 10 cm. The resultant force on the charge
 
     at C is
     1) 0.9 N    
     2) 1.8 N
     3) 2.7 N    4) 3.6 N
 
 32.    The electric field due to a charge at a distance of 3 m from it is 500 N / coulomb. The magnitude of the charge it is
 
     
     1) 2.5 micro-coulomb
     2) 2.0 micro-coulomb
     3) 1.0 micro-coulomb
     4) 0.5 micro-coulomb
 
 33.    In the figure, distance of the point from A where the electric field is zero is
 
 
 
 
     1) 20 cm    2) 10 cm
     3) 33 cm    4) 15 cm
 
 34.    When 1019 electrons are removed from a neutral metal plate, the electric charge on it is (in coulomb)?
     1) +1.6    2) –1.6
     3) 10–19    4) 1019
 
 35.    The unit of intensity of electric field is?
     1) Newton / coulomb
     2) Joule / coulomb
     3) volt / meter2
     4) Newton / meter
 
 36.    Two point charges q1 and q2 are 3 m apart and their combined charge is 20 mC. If one repels the other with a force of 0.075 N, what are the two charges?
     1) 1mc, 11mc    2) 5mc, 15mc
      3) 4mc, 14mc    4) 2mc, 10mc
 
 37.    An electron is sent into an electric field of intensity 9.1 × 106 NC–1. The acceleration produced is?
     1) 1.4 × 1018 ms–2
     2) 1.6 × 1016 ms–2
     3) 1.4 × 108 ms–2
     4) 1.6 × 1018 ms–2
 
 38.    A metal sphere of radius 10cm has a charge of 12.56×10–6 coulomb. The surface charge density on the sphere is?
     1) 10–2 c/m2    2) 10–1 c/m2
     3) 10–3 c/m2    4) 10–4 c/m2
 
 39.    The capacity of spherical conductor of radius R is?
     1) 4pe0R    2) 8pe0R
     3) (4pe0) / R    4) R
 
 40.    A point chare 7.5 mC is kept at the origin. Find the magnitude of strength of electric field at (4m, 3m)?
     1) 1.7 × 103 NC–1
     2) 2.7 × 103 NC–1
     3) 1.7 × 102 NC–1
     4) 2.7 × 102 NC–1
 
 
 KEY

 1) 2    2) 3    3) 1    4) 4
 5) 1    6) 1    7) 3    8) 3
 9) 3    10) 4    11) 4    12) 2
 13) 2    14) 2    15) 4    16) 2
 17) 1    18) 4    19) 2    20) 1
 21) 1    22) 3    23) 1    24) 4
 25) 1    26) 3    27) 3    28) 2
 29) 4    30) 4    31) 2    32) 4
 33) 3    34) 1    35) 1    36) 2
 37) 4    38) 4    39) 1    40) 2