MCQ’s ON THERMODYNAMICS & LAWS OF MOTION
Q- Consider three masses of 1kg, 3kg and 6kg which are connected to each other and are placed horizontally on the table. Calculate the acceleration of this system. Consider g = 10m/s.
(a) 3
(b) 0
(c) 1
(d) 2
Answer: (d) 2
Q- From the following diagram, select the correct diagram when a vessel containing water is given a constant acceleration towards the right along the straight line.
Answer: (c)
Q- Consider a man standing on the spring balance such that the reading on the spring balance is 60kg. If the man jumps out of the spring balance what will be the final reading of the spring balance?
(a) Remains unchanged
(b) Increases
(c) Decreases
(d) First increases then decrease to zero
Answer: (d) First increases then decreases to zero
Q- Which of the following should be constant for a body to have a constant momentum?
(a) Acceleration
(b) Force
(c) Velocity
(d) All of the above
Answer: (d) All of the above
Q- Choose the correct statement
(a) A body can be accelerated by frictional force
(b) There can be zero friction
(c) Kinetic friction is greater than rolling friction
(d) Frictional force and area of contact between the two surfaces are proportional
Answer: (c) Kinetic friction is greater than rolling friction
Q- Consider a car that overturns while taking a turn. Select the option that is experienced by the wheels of the car.
(a) First, both inner, as well as the outer wheel, leave the ground
(b) First, the inner wheel leaves the ground
(c) The inner wheel experiences no change
(d) None of the above
Answer: (b) First, the inner wheel leaves the ground
Q- Let two bodies be with masses 2kg and 5kg respectively. Let these bodies be at rest with the same force acting on them. Calculate the ratio of times that is required by both the bodies to reach the final velocity.
(a) 2:5
(b) 25:4
(c) 5:3
(d) 4:25
Answer: (a) 2:5
Q- Let A, B, and C be the three blocks of mass 2kg each. These blocks are hanging over a pulley with the help of a string. What is the tension produced by the string connecting B and C?
(a) 3.3N
(b) 0
(c) 13.1N
(d) 19.6N
Answer: (c) 13.1N
Q- Following is the diagram of the thermodynamic process. Refer the diagram and match the following?
P Process – I (a) Adiabatic
Q Process – II (b) Isobaric
R Process – III (c) Isochoric
S Process – IV (d) Isothermal
(a) (P,c), (Q,d), (R,b), (S,a)
(b) (P,c), (Q,d), (R,b), (S,a)
(c) (P,a), (Q,c), (R,d), (S,b)
(d) (P,c), (Q,a), (R,d), (S,b)
Answer: (d) (P,c), (Q,a), (R,d), (S,b)
Q- Which of the following process is used to do maximum work done on the ideal gas if the gas is compressed to half of its initial volume?
(a) Isothermal
(b) Isochoric
(c) Isobaric
(d) Adiabatic
Answer: (d) Adiabatic
Q- The coefficient performance of a refrigerator is 5. If the temperature inside the freezer is -20℃, calculate the heat rejected to the surrounding
(a) 11℃
(b) 41℃
(c) 21℃
(d) 31℃
Answer: (d) 31℃
Q- A thermodynamic system is explained with the help of the graph ABCD. What is the heat rejected by the system during the cycle?
(a) pV
(b) 2pV
(c) 4pV
(d) 1/2pV
Answer: (b) 2PV
Q- Select the incorrect statement
(a) For the triple point of water, 1°K is equal to 1/273.16.
(b) The first law of thermodynamics is also known as the law of thermal equilibrium
(c) The triple point of water is one of the reference points on the thermodynamic scale of temperature
(d) At room temperature, the heat of combustion is not found
Answer: (d) At room temperature, the heat of combustion is not found
Q- What is a necessary condition for a reaction to be spontaneous at all temperatures?
(a) ΔH < ΔG
(b) ΔG and ΔH should be positive
(c) ΔH = ΔG = 0
(d) ΔG and ΔH should be negative
Answer: (d) ΔG and ΔH should be negative
Q- A gas is compressed to half of its initial volume isothermally. The same gas is compressed again until the volume reduces to half through an adiabatic process. Then
(a) Work done during isothermal compression is more
(b) Work done is independent of the processes used for compression
(c) Work done is more during the adiabatic process
(d) Work done is dependent on the atomicity of the gas
Answer: (c) Work done is more during the adiabatic process
Q- Select the factor that affects the heat of reaction which is based on Kirchoff’s equation
(a) Molecularity
(b) Temperature
(c) Pressure
(d) Volume
Answer: (b) Temperature
Q- For all the reactions what is the nature of the chemical dissociation?
(a) Exothermic
(b) Reversible
(c) Endothermic
(d) Reversible and endothermic
Answer: (d) Reversible and endothermic
Q- Which of the following is the largest unit of energy
(a) Electron volt
(b) Joule
(c) Calorie
(d) Erg
Answer: (c) Calorie
