All Free Physics MCQs with Answers
Every Physics question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,934 questions · page 676 of 697
- A. isobaric process
- B. adlabalic process
- C. isothermal process
- D. isochoric process
Explanation: The adiabatic process is performed quickly when the system is perfectly insulated from the surrounding environment.
Correct answer: adlabalic process13502. Which of the following makes the motion of a perpetual motion machine a physical impossibility?
- A. fist law of thermodynamics
- B. second law of thermodynamics
- C. third law of thermodynamics
- D. None of these
Explanation: As the second law of thermodynamics states, the more energy is transformed, the more is wasted.
Correct answer: second law of thermodynamics- A. No heat enters or leaves the system
- B. The temperature remains constant
- C. All work is mechanical
- D. Energy is conserved
Explanation: The first law of thermodynamics states that energy can neither be created nor destroyed, it is converted from one form to another…
Correct answer: Energy is conserved- A. Work done
- B. Exchange of heat
- C. Change in temperature
- D. Change in internal energy
Explanation: An adiabatic process is defined as a process in which no heat transfer takes place.
Correct answer: Exchange of heat- A. The work done by the gas
- B. The work done on the gas.
- C. Change in the internal energy of the gas
- D. Zero, since the process is isothermal
Explanation: During an isothermal process, temperature and internal energy remain unchanged.
Correct answer: The work done by the gas13506. A heat engine:
- A. Converts heat input to an equivalent amount of work
- B. Converts work to an equivalent amount of heat
- C. Takes heat in, does work, and loses energy as heat
- D. Uses positive work done on the system to transfer heat from a low temperature reservoir to a high temperature reservoir
Explanation: A heat engine is a device that operates on the principle of converting heat energy into mechanical work, often by using a working…
Correct answer: Converts heat input to an equivalent amount of work- A. Velocity
- B. Viscosity of fluid
- C. Density of the body
- D. All of above
Explanation: When a body falls through a fluid, it experiences a resistance force due to the viscosity of the fluid.
Correct answer: All of above- A. Spherical shape
- B. Oblong shape
- C. Rectangular shape
- D. Curve shape
Explanation: Stokes' Law holds true for bodies that have a spherical shape. It describes the motion of a small spherical particle through a viscous…
Correct answer: Spherical shape- A. Weight in water
- B. Weight in liquid
- C. Weight in air
- D. Volume
Explanation: According to the Archimedes principle, if an object is immersed in a fluid, it experiences an apparent loss of weight which is equal to…
Correct answer: Volume- A. Will be pulled towards each other
- B. Will drift apart from each other
- C. Will have no effect on each other
- D. Will experience random motion
Explanation: As the speed of water between the ships is greater than outside them, pressure between them gets reduced, and pressure outside is greater…
Correct answer: Will be pulled towards each other- A. 4.9 x 10^-3 m3/s
- B. 4.9 m3/s
- C. 7.0 m3/s
- D. 49 m3/s
Explanation: We are asked to find the volume rate of flow in this question. With the radius 1.5cm (0.015m) we can find the cross-sectional area of the…
Correct answer: 4.9 x 10^-3 m3/s- A. Zero
- B. Minimum but not zero
- C. Large
- D. Peripheral
Explanation: b) Minimum but not zeroThis option suggests that the velocity of the liquid in contact with the containing vessel is the minimum but not…
Correct answer: Minimum but not zero- A. Log2
- B. 1/log λ
- C. 1/λ
- D. (Log2)-1
Explanation: We have to remember formulaMean life = 1/lambda Half life = log2 / lambda =log2 × 1/lambdaReplacing 1/lambda by mean life,Half life = log2…
Correct answer: (Log2)-1- A. 0.1
- B. 0.2
- C. 0.3
- D. 2.3
Explanation: T1/2 = 0.693/λ.Where T1/2= half life and λ= decay constant When half life= 2.3 daysSo λ = 0.693/T1/2= 0.693/2.3=0.30 per day
Correct answer: 0.3- A. 22 years
- B. 88 years
- C. 11 years
- D. 44 years
Explanation: The correct answer is 44 years because the half-life of a sample is defined as the time required for half of the sample to decay.
Correct answer: 44 years- A. N0/8
- B. 2N0/3
- C. N0/3
- D. 7N0/8
Explanation: Each half-life reduces the remaining number of nuclei by half. After one half-life, N0/2 nuclei remain.
Correct answer: 7N0/8- A. X/32
- B. X/13
- C. X/8
- D. X/5
Explanation: Half life is 2.6 yearsInitially x grams of sodium isotope were present After 13 years which is 13/2.6 = 5 years Let the amount of sodium…
Correct answer: X/32- A. 12 hours
- B. 6 hours
- C. 2 hours
- D. 3 hours
Explanation: Original amount = 16gDecayed amount = 12gradioactive isotope left after 6 hours is, 16 g - 12 g = 4 gUse N = No/2nWhere N = 4g , No =…
Correct answer: 3 hours- A. m1:m2
- B. √m1/m2
- C. m1²: m2²
- D. √m1:√m2
Explanation: The energy and momentum are related The KE is proportional to square of momentum KE = p²/2m so if two bodies have equal energy then their…
Correct answer: √m1/m2- A. 12
- B. 144
- C. 72
- D. 48
Explanation: To determine the kinetic energy of the mass after 4 seconds, apply Newton's second law.
Correct answer: 144