Physics Concepts for Everyday Science

Physics for Competitive Exams

Everyday Science is a compulsory CSS paper (100 marks) and physics concepts form about 25-30% of its content. PPSC and FPSC MCQ tests also include basic physics questions regularly.

1. Mechanics - Basic Concepts

• Newton's Laws of Motion:
  • 1st Law: Object at rest stays at rest (inertia)
  • 2nd Law: F = ma (Force equals mass times acceleration)
  • 3rd Law: Every action has an equal and opposite reaction
• Gravity: g = 9.8 m/s" on Earth, discovered by Newton
• Energy: Cannot be created or destroyed, only transformed

2. Heat & Thermodynamics

• Heat transfers via conduction, convection, and radiation
• Water boils at 100C (212F) at sea level
• Water freezes at 0C (32F)
• Absolute zero: -273.15C (0 Kelvin) - lowest possible temperature

3. Light & Optics

• Speed of light: 3 x 10^8 m/s in vacuum
• Colors of spectrum: VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange, Red)
• Mirrors: Concave (converging), Convex (diverging)
• Lenses: Convex (for farsightedness), Concave (for nearsightedness)

4. Electricity & Magnetism

• Ohm's Law: V = IR (Voltage = Current x Resistance)
• Electric current measured in Amperes
• Resistance measured in Ohms
• Power: P = VI (measured in Watts)
• Transformer: Steps up or steps down AC voltage

5. Modern Physics

• Atom: Protons (positive), Neutrons (neutral), Electrons (negative)
• Radioactivity: Alpha, Beta, Gamma radiation
• E = mc2: Einstein's mass-energy equivalence
• Nuclear fission: Splitting atoms (nuclear power plants)
• Nuclear fusion: Combining atoms (sun's energy source)

6. Frequently Asked Questions in PPSC/FPSC

• What causes a rainbow? (Dispersion of light)
• Why is the sky blue? (Rayleigh scattering)
• Unit of electric current? (Ampere)
• Who discovered X-rays? (Wilhelm Rontgen)
• Speed of sound in air? (About 343 m/s at 20C)