⭐ Sabse Important Points · एक नज़र में
- SI Base Units: Seven fundamental units: metre (length), kilogram (mass), second (time), ampere (current), kelvin (temperature), mole (amount), candela (luminous intensity).
- Work-Energy Theorem: Net work done on an object equals change in its kinetic energy (W = ΔKE).
- Newton's Second Law: Force equals mass times acceleration (F = ma). It gives the quantitative definition of force.
- Power: Rate of doing work; SI unit watt (W). 1 W = 1 J/s. Commercial unit of energy: kilowatt-hour (kWh).
- Equations of Motion: For uniform acceleration: v = u + at; s = ut + ½at²; v² = u² + 2as.
- Human Blood: Plasma (55%) + formed elements (45%). RBCs contain haemoglobin for oxygen transport; WBCs for immunity; platelets for clotting.
Introduction · परिचय
General Science for UPPSC covers fundamental concepts from Physics, Chemistry, and Biology that are frequently asked in Prelims and Mains. This revision note focuses on high-yield topics: units and measurement, motion, work-energy-power, human body systems, and basic chemical principles. Emphasis is on conceptual clarity and application-based questions.
Units, Measurement, and Motion
Physics begins with measurement. The SI system has seven base units. Motion is described by displacement, velocity, and acceleration. Newton's laws explain force and motion. Kinematic equations apply to uniformly accelerated motion.
📐 Formula / Rule Box · सूत्र याद रखो
Newton's Second Law
F = m × a
First Equation of Motion
v = u + at
Second Equation of Motion
s = ut + ½at²
Third Equation of Motion
v² = u² + 2as
Newton's Second Law
Force equals mass times acceleration (F = ma). It gives the quantitative definition of force.
Equations of Motion
For uniform acceleration: v = u + at; s = ut + ½at²; v² = u² + 2as.
⭐ Key Points · याद रखने वाली बातें
- SI Base Units: Seven fundamental units: metre (length), kilogram (mass), second (time), ampere (current), kelvin (temperature), mole (amount), candela (luminous intensity).
- Scalar vs Vector: Scalars have magnitude only (distance, speed); vectors have magnitude and direction (displacement, velocity, acceleration).
✍️ Solved Example 1 · हल किया हुआ उदाहरण
❓ Question: A car accelerates uniformly from rest to 20 m/s in 5 s. Find its acceleration and distance covered.
✅ Solution: Acceleration = 4 m/s²; Distance = 50 m
💡 Explanation: Using v = u + at: 20 = 0 + a×5 ⇒ a = 4 m/s². Using s = ut + ½at²: s = 0 + ½×4×25 = 50 m.
Work, Energy, Power, and Human Body Systems
Work is done when force causes displacement. Energy is capacity to do work; it exists in forms like kinetic, potential, and chemical. Power is rate of doing work. In biology, human body systems (digestive, circulatory, respiratory, nervous) are frequently asked. Key concepts include blood composition, heart chambers, and respiratory pigments.
📐 Formula / Rule Box · सूत्र याद रखो
Work
W = F × s × cosθ
Kinetic Energy
KE = ½mv²
Power
P = W/t
Work-Energy Theorem
Net work done on an object equals change in its kinetic energy (W = ΔKE).
| Arteries | Veins |
|---|---|
| Carry blood away from heart | Carry blood towards heart |
| Thick, elastic walls | Thin, less elastic walls |
| Carry oxygenated blood (except pulmonary artery) | Carry deoxygenated blood (except pulmonary vein) |
⭐ Key Points · याद रखने वाली बातें
- Power: Rate of doing work; SI unit watt (W). 1 W = 1 J/s. Commercial unit of energy: kilowatt-hour (kWh).
- Human Blood: Plasma (55%) + formed elements (45%). RBCs contain haemoglobin for oxygen transport; WBCs for immunity; platelets for clotting.
- Heart Chambers: Four chambers: right atrium, right ventricle, left atrium, left ventricle. Left ventricle pumps oxygenated blood to body via aorta.
✍️ Solved Example 1 · हल किया हुआ उदाहरण
❓ Question: A force of 10 N displaces an object by 2 m in the direction of force. Calculate work done and power if time taken is 4 s.
✅ Solution: Work = 20 J; Power = 5 W
💡 Explanation: Work = F × s = 10 × 2 = 20 J. Power = Work/time = 20/4 = 5 W.
Practice Questions · खुद हल करके देखो
पहले खुद try karo, phir “Answer dekho” dabakar check karo. 👇
Q1Which of the following is a vector quantity? (a) Speed (b) Distance (c) Displacement (d) Mass
👀 Answer dekho
✅ Answer: (c) Displacement
💡 Explanation: Displacement has both magnitude and direction, so it is a vector. Speed, distance, and mass are scalars.
Q2The SI unit of power is: (a) Joule (b) Newton (c) Watt (d) Pascal
👀 Answer dekho
✅ Answer: (c) Watt
💡 Explanation: Power is rate of doing work; its SI unit is watt (W), where 1 W = 1 J/s.
Q3Which blood cells are primarily responsible for oxygen transport? (a) WBCs (b) RBCs (c) Platelets (d) Plasma
👀 Answer dekho
✅ Answer: (b) RBCs
💡 Explanation: Red blood cells contain haemoglobin, which binds oxygen and transports it from lungs to tissues.
⚠️ Common Mistakes · ये गलतियाँ बिल्कुल मत करना
- Confusing speed with velocity: Speed is scalar, velocity is vector. Always check direction in numericals.
- Forgetting exceptions in artery/vein comparison: Pulmonary artery carries deoxygenated blood, pulmonary vein carries oxygenated blood.
- Using wrong formula for work when force and displacement are not in same direction: Use W = F s cosθ.
⚡ Quick Revision · Exam से पहले 2 मिनट में दोहराओ
- SI Base Units: Seven fundamental units – metre, kilogram, second, ampere, kelvin, mole, candela.
- Equations of Motion: Three equations for uniform acceleration – v=u+at, s=ut+½at², v²=u²+2as.
- Human Heart: Four chambers; left ventricle strongest; arteries carry blood away from heart.