Work, Energy and Power NEET QUESTIONS

Work, Energy, and Power  (NEET One-Word Questions)

No.	Question	Answer	Explanation
1	What is the SI unit of work?	Joule	Work is defined as force × displacement. The SI unit is Newton × meter = Joule (J).
2	What is the work done when force is perpendicular to displacement?	Zero	Work = F·d·cosθ. If θ = 90°, cos90° = 0 → Work = 0.
3	What kind of quantity is work?	Scalar	Work has magnitude but no direction → scalar quantity.
4	What is the energy possessed due to motion?	Kinetic	Energy due to motion is called kinetic energy  (½mv²).
5	What is the energy possessed due to position?	Potential	Energy stored due to position or configuration is potential energy (mgh).
6	What is the SI unit of power?	Watt	Power = Work / Time. SI unit is Joule/second = Watt (W).
7	What is the power of a body that does 100 J of work in 2 seconds?	50	Power = Work/Time = 100/2 = 50 W.
8	Which law is associated with conservation of energy?	First	The first law of thermodynamics is the law of conservation of energy.
9	What is the work done by gravity in vertical free fall?	Positive	Gravity and displacement are in the same direction → Work done = positive.
10	What is the work done in uniform circular motion?	Zero	Displacement is perpendicular to force (centripetal) → Work = 0.
11	What is the rate of doing work called?	Power	Power is defined as the rate at which work is done.
12	Which physical quantity is conserved in absence of external force?	Energy	In an isolated system (no external force), total mechanical energy is conserved.
13	What is the relation between KE and momentum?	p²/2m	K.E. = p²/2m, where p = momentum, m = mass.
14	What is the power of a machine that consumes 1 Joule per second?	1	1 Joule per second = 1 Watt.
15	What is the unit of energy in CGS system?	Erg	In CGS, energy is measured in ergs. (1 J = 10⁷ erg).
16	What is the instantaneous power for zero force?	Zero	Power = F·v. If F = 0 → Power = 0.
17	What type of work is done against gravity?	Negative	When lifting a body, force and gravity are opposite → Work done by gravity = negative.
18	What is the energy of an object at rest on the ground?	Zero	Kinetic = 0 (no motion), Potential = 0 (reference level) → Total energy = 0.
19	Which form of energy is stored in a stretched spring?	Potential	A stretched or compressed spring stores elastic potential energy.
20	What is the total energy at maximum height in projectile motion?	Constant	At max height: KE ↓, PE ↑, but total mechanical energy = constant (if no air resistance).