Free Work MCQs with Answers
169 Work MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Work is done when a force produces displacement, with its value determined by the component of force along the displacement. The topic covers positive, negative and zero work, work by variable forces from force-displacement graphs, and the connection between net work and change in kinetic energy.
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169 questions · page 2 of 9
- A. 45°
- B. 90°
- C. 180°
- D. 0°
Explanation: Work is W = Fd cos θ. For fixed force and displacement, cos θ is greatest at θ = 0°, where W = Fd, so the work is maximum.
Correct answer: 0°- A. friction
- B. electric
- C. gravitational
- D. magnetic
Explanation: Friction is non-conservative because the work it does depends on the path and mechanical energy is converted into thermal energy.
Correct answer: friction- A. always positive
- B. always negative
- C. positive only for small frictional force
- D. positive only for large frictional force
Explanation: For ordinary friction opposing the motion, the angle between friction and displacement is 180°, so W = Fs cos 180° = -Fs, making the work…
Correct answer: always negative- A. force into small interval
- B. displacement into small interval
- C. both force and displacement into small intervals
- D. force into small and displacement into large intervals
Explanation: For a variable force, the displacement is divided into small intervals and the work over each interval is approximated by F Δs, then these…
Correct answer: displacement into small interval- A. zero
- B. minimum
- C. infinity
- D. maximum
Explanation: Work is W = Fs cos θ. When the force is parallel to displacement, θ = 0° and cos 0° = 1, so W = Fs, the maximum possible work for fixed…
Correct answer: maximum26. Work is a:
- A. Vector quantity
- B. Scalar quantity
- C. Sometimes scalar sometimes vector
- D. None of these
Explanation: Work has only a magnitude but no direction. The formula for work is written as a dot product of force and displacement.
Correct answer: Scalar quantity- A. at any instant
- B. averagely
- C. during its operation
- D. during one cycle
Explanation: The enclosed area in a PV diagram for a thermodynamic cycle represents the net work done by the system during one cycle.
Correct answer: during one cycle- A. Isothermal expansion
- B. Adiabatic expansion
- C. Isobaric process
- D. Isochoric processIn an isochoric (constant volume) process, no work is done because there is no change in volume. However, the other processes listed involve some work done by the system, but the maximum work is done in an isobaric process, where pressure remains constant.
Explanation: In an isochoric (constant volume) process, no work is done because there is no change in volume.
Correct answer: Isochoric processIn an isochoric (constant volume) process, no work is done because there is no change in volume. However, the other processes listed involve some work done by the system, but the maximum work is done in an isobaric process, where pressure remains constant.- A. Gradient of the tangent of the curve of P-V graph
- B. Gradient of the tangent of the curve of P-T graph
- C. Area of the curve under the P-V graph
- D. Area of the curve under the P-T graph
Explanation: The work done (W) in a thermodynamic process can indeedbe calculated by finding the area under the P-V graph (pressure-Volume…
Correct answer: Area of the curve under the P-V graph- A. Adiabatic
- B. Isobaric
- C. Isochoric
- D. Isothermal
Explanation: For given expansion from V₁ to V₂, the work done is the area under the P-V curve.
Correct answer: Isobaric- A. Free expansion
- B. An isothermal expansion
- C. Isobaric
- D. An expansion at constant temperature
Explanation: The formula W = PΔV = P(V₂-V₁) calculates work done under the condition that pressure (P) is constant throughout the process.
Correct answer: Isobaric- A. PΔV
- B. VΔP
- C. nRT ln(V₂/V₁)
- D. Zero
Explanation: In isobaric process, pressure is constant, work done is W = PΔV, where P is constant pressure and ΔV is change in volume.
Correct answer: PΔV- A. Zero
- B. P/V
- C. -P/V
- D. V/P
Explanation: For isothermal process, PV = constant. Differentiating, P dV + V dP = 0, so dP/dV = -P/V, which is slope of the PV curve.
Correct answer: -P/V- A. During the process AB work done by the gas is positive
- B. During the process AB work done by the gas is negative
- C. During the process BC internal energy of the gas is increasing
- D. None of these
Explanation: We know that,f(density)=nM/V [Mass=moles×Molar mass](Volume)so,V= nM/V (i)In process AB f is constant,Also, V→constant [By eq -…
Correct answer: During the process AB work done by the gas is positive- A. Gradient of the tangent of the curve of P-V graph
- B. Gradient of the tangent of the curve of P-T graph
- C. Area of the curve under the P-V graph
- D. Area of the curve under the P-T graph
Explanation: To calculate the work done on the object, we must calculate the area under the curve of a P-V graph.
Correct answer: Area of the curve under the P-V graph- A. W2 > W1 > W3
- B. W1 > W2 > W3
- C. W2 > W3 > W1
- D. W1 > W3 > W2
Explanation: Wisobaric > Wisothermal > Wadiabatic Isothermal Process: In an isothermal process, the expansion of the gas occurs at a constant…
Correct answer: W2 > W1 > W3- A. Isothermal
- B. Adiabatic
- C. Isochoric
- D. Isobaric
Explanation: The correct answer is D, 'Isobaric'. In an isobaric process, the pressure remains constant, and the work done by the system involves a…
Correct answer: Isobaric- A. PV
- B. 3PV
- C. 2PV
- D. 4PV
Explanation: Work done = area under the P-V curve. W = LM x MN W = (2P-P) x (2V - V) W = P x V W = 1PV
Correct answer: PV- A. P∆U
- B. P∆A
- C. P∆V
- D. All are correct
Explanation: P∆V is the correct expression for work done by gas because it represents the amount of energy required to move the piston against the…
Correct answer: P∆V- A. 90°
- B. 0°
- C. 30°
- D. 60°
Explanation: Solution:- Use relation; W= Fd cosθ If θ is 60 degrees, cos(60°) = 1/2 = 0.5.
Correct answer: 60°