Free Work and Energy MCQs with Answers
748 Work and Energy 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 transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
Last updated
Read the Work and Energy notesFree MDCAT chapter notes with key terms748 questions · page 6 of 38
- A. Always higher
- B. Always lower
- C. Equal
- D. Sometimes higher
Explanation: A real heat engine has irreversibilities (e.g., friction, heat loss), making its efficiency lower than that of an ideal Carnot engine…
Correct answer: Always lower- A. 10% to 20%
- B. 20% to 35%
- C. 35% to 40%
- D. 40% to 50%
Explanation: The efficiency of a diesel engine can vary depending on various factors such as the design of the engine, operating conditions, and…
Correct answer: 35% to 40%- A. 80oC ,37oC
- B. 99oC , 30oC
- C. 99oC,25oC
- D. 99oC , 37oC
Explanation: Efficiency of Engine , = Work / QinputAs, W = 1 / 6 Qinput = 1 / 6Also, = 1 - T2 / T1WhereT1 and T2 are the temperatures of the source and…
Correct answer: 99oC , 37oC- A. 10%
- B. 20%
- C. 30%
- D. 50%
- E. 70%
Explanation: The maximum theoretical efficiency of the system is the one corresponding to the efficiency of a Carnot cycle operating between the same…
Correct answer: 50%- A. 4.00
- B. 1.00
- C. 0.25
- D. Impossible to determine
Explanation: Efficiency= Output work/ Input workAs input energy is 4 times the useful work done. Efficiency=¼=0.25Hence,C is the correct option.
Correct answer: 0.25- A. 10% to 20%
- B. 20% to 35%
- C. 35% to 40%
- D. 40% to 50%
Explanation: c) 35% to 40%:Option (c) "35% to 40%" is also a possible range of efficiency percentages for certain advanced and well-optimized diesel…
Correct answer: 35% to 40%- A. 1/2
- B. 1/4
- C. 3/4
- D. 1
Explanation: Option A is correct since the formula of efficiency for a heat engine is 1-(T2/T1).
Correct answer: 1/2- A. 50%
- B. 25%
- C. 12.5%
- D. 6.25%
Explanation: Boiling point of water= 100° =373KFreezing point of water=0° = 273KThe formula for efficiency; =1-TCold/Thotx100 = 1- 273/373x100 =26.80%…
Correct answer: 25%- A. Nuclear reactor
- B. Storage battery
- C. Silicon solar cell
- D. Dry battery cell
Explanation: a) Nuclear reactor: A nuclear reactor is a device that generates electricity by harnessing the energy released during nuclear reactions…
Correct answer: Nuclear reactor- A. 2 J
- B. 4 J
- C. 8 J
- D. 16 J
Explanation: K.E = 1/2 m Δv2 = 1/2 m (Vf2 - Vi2)K.E = 1/2 x 1 x (22 - 62)K.E = 0.5 x (-32) = -16JNeglect the negative sign.
Correct answer: 16 J- A. 490 J
- B. 98 J
- C. 49 J
- D. 980 J
Explanation: Gain in K.E = Loss in Gravitational P.EK.E= mg(h1 - h2)= (1)(9.8)(50 - 40) = 9.8(10) = 98 J
Correct answer: 98 J112. If a stone of mass 500g is dropped from height 20m then kinetic energy while hitting the ground is :
- A. 10 J
- B. 40 J
- C. 75 J
- D. 100 J
Explanation: As the potential energy of an object at the highest point converts into KE while going downhence, KE=mgh 500g=0.5kg =0.5*10*20 =100
Correct answer: 100 J- A. Mass 3M and speed v
- B. Mass 2M and speed 3v
- C. Mass 3M and speed 2v
- D. Mass M and speed 4V
Explanation: K.E = 1/2Mv2The K.E will be maximum when the product of "M" and "v²" is maximum. In (B) the product has maximum value i.e. 9Mv².
Correct answer: Mass 2M and speed 3v- A. 10 J
- B. 40 J
- C. 75 J
- D. 100 J
Explanation: K.E = 1/2 mv2 = 1/2 (500 x 10-3) (20)2 =200/2 =100J
Correct answer: 100 J- A. Quartered
- B. One third
- C. Twice
- D. Remain same
Explanation: Option d) Remain same is the correct option. When the speed of an object is halved and the mass is quadrupled, the kinetic energy remains…
Correct answer: Remain same- A. 17 m s-1
- B. 21 m s-1
- C. 25 m s-1
- D. 10 m s-1
Explanation: To determine the speed of the vehicle when it covers a distance of 30 m, we can use Newton's second law of motion:F = ma In this case, the…
Correct answer: 21 m s-1- A. 5/9.8J
- B. 500 x 20J
- C. 500/9.8 J
- D. 500/20/9.8J
Explanation: The explanation of this question is: Increase in potential energy P.E. = Final P.E. - Initial P.E.
Correct answer: 500 x 20J- A. There is some force of friction involved during the motion of the body
- B. There is no force of friction involved during the motion of the body
- C. There is greater force of friction involved during the motion of the body
- D. Both; there is some force of friction involved during the motion of the body & no force of friction involved during the motion of the body
- E. None of the above
Explanation: The principle of conservation of mechanical energy states that the total mechanical energy in a system remains constant when only…
Correct answer: There is no force of friction involved during the motion of the body- A. 5.6 kms-1
- B. 11.2 kms-1
- C. 22.4 kms-1
- D. 33.6 kms-1
Explanation: escape velocity = √ (2GM / r)where: G= gravitation constantM = mass of the earthr = radius of earth2 and G are constant in this equation…
Correct answer: 22.4 kms-1- A. S = G
- B. S = 2G
- C. G = 2S
- D. None of these
Explanation: At equilibrium position x = mg / kUspring = (1/2) k x² = (1/2) k (mg / k) x = mgx / 2 = (1/2) (loss in G.P.E.) ⇒ G = 2S
Correct answer: G = 2S