Physics is a scoring part of the ECET 2026 General Science section for CSE diploma students, and the topic Work, Energy & Power is often featured in both APECET and TSECET exams. This concept is not only important in academics but also in real-world engineering applications. Let’s simplify it, understand the key formulas, and master 10 MCQs that are most expected for ECET.
📘 Concept Notes – Work, Energy & Power
🔨 Work (W)
- Definition: Work is said to be done when a force is applied on an object and the object is displaced in the direction of the force.
- Formula: W=F×d×cos(θ)W = F \times d \times \cos(\theta)W=F×d×cos(θ) where:
- FFF = Force
- ddd = Displacement
- θ\thetaθ = Angle between force and displacement
- SI Unit: Joule (J)
- Types of Work:
- Positive Work – Force and displacement in same direction
- Negative Work – Force and displacement in opposite direction
- Zero Work – No displacement
⚡ Energy (E)
- Definition: Energy is the capacity to do work.
- Types:
- Kinetic Energy (KE): KE=12mv2KE = \frac{1}{2}mv^2KE=21mv2
- Potential Energy (PE): PE=mghPE = mghPE=mgh
- Mechanical Energy = KE + PE
- Unit: Joule (J)
🚀 Power (P)
- Definition: Power is the rate at which work is done.
- Formula: P=WtP = \frac{W}{t}P=tW or P=EtP = \frac{E}{t}P=tE
- Unit:Watt (W)
- 1W=1Joule/sec1\text{W} = 1 \text{Joule/sec}1W=1Joule/sec
🧠 Other Key Points:
- 1 kW = 1000 W
- 1 HP (Horsepower) = 746 W
- Law of Conservation of Energy: Energy can neither be created nor destroyed, only transformed.
- If no energy is lost, mechanical energy remains constant.
🔟 10 Most Expected MCQs – ECET 2026 [Work, Energy & Power]
Q1. The SI unit of Work is:
A) Watt
B) Newton
C) Joule
D) Erg
Q2. A man lifts a 10 kg object to a height of 2 m. What is the potential energy? (g = 9.8 m/s²)
A) 10 J
B) 19.6 J
C) 196 J
D) 98 J
Q3. What is the formula for Kinetic Energy?
A) mv
B) mgh
C) ½mv²
D) F × d
Q4. What is the power if 200 J of work is done in 4 seconds?
A) 800 W
B) 50 W
C) 100 W
D) 25 W
Q5. When is the work done said to be zero?
A) When object moves
B) When force is applied
C) No displacement
D) Force and displacement are in same direction
Q6. 1 Horsepower = ?
A) 1000 W
B) 746 W
C) 500 W
D) 1500 W
Q7. If a moving object comes to rest, its kinetic energy becomes:
A) Maximum
B) Same
C) Zero
D) Infinite
Q8. What type of energy is stored in a stretched spring?
A) Kinetic Energy
B) Electrical Energy
C) Potential Energy
D) Thermal Energy
Q9. Unit of Power is:
A) Newton
B) Joule
C) Watt
D) Meter
Q10. The total mechanical energy of a freely falling body is:
A) Zero
B) Increasing
C) Constant
D) Decreasing
✅ Answer Key Table
| Q.No | Answer |
|---|---|
| Q1 | C |
| Q2 | C |
| Q3 | C |
| Q4 | B |
| Q5 | C |
| Q6 | B |
| Q7 | C |
| Q8 | C |
| Q9 | C |
| Q10 | C |
🧠 Explanations of All Answers
- Q1 → C: Work is measured in Joules (J).
- Q2 → C: PE = mgh = 10 × 9.8 × 2 = 196 J.
- Q3 → C: Kinetic Energy = ½mv².
- Q4 → B: Power = Work/Time = 200/4 = 50 W.
- Q5 → C: Work is zero when there is no displacement.
- Q6 → B: 1 HP = 746 W (standard conversion).
- Q7 → C: If object stops, velocity = 0, hence KE = 0.
- Q8 → C: A stretched spring stores potential energy.
- Q9 → C: Watt is the SI unit of Power.
- Q10 → C: In absence of resistance, total mechanical energy remains constant.
🎯 Why This Practice Matters for ECET 2026
Work, Energy, and Power questions are easy, direct, and frequently repeated in ECET. These topics offer straightforward scoring opportunities if your basics are clear. Practice helps you quickly eliminate wrong options and solve numericals within seconds, which is key to securing top ranks.
📲 Join Our ECET Prep Community on Telegram
Get PDF notes, mock questions, and exam tips every day!
👉 @LearnNewThingsHub
Join 10,000+ students already preparing smartly for ECET 2026!
