3.1 General Science — Physics & Everyday Phenomena

Scope of General Science for VAO

The VAO exam tests General Science up to the 10th-standard (SSLC) level. The questions are broad but shallow — they reward recall of definitions, units, and examples rather than derivation or multi-step problem solving. Karnataka SSLC syllabus aligns closely with NCERT Class 6–10 content, so either set of textbooks works for preparation.

High-Yield Sub-Topic Map

Physics — Key Concepts and Formulas

Motion

• Speed = distance / time (m/s in SI)
• Velocity = displacement / time (vector — has direction)
• Acceleration = change in velocity / time (m/s²)
• Equation of motion (uniform): v = u + at

Force and Newton's Laws

Work, Energy, Power

• Work = force × displacement (W = Fs); SI unit joule (J)
• Kinetic energy = ½mv²
• Potential energy = mgh
• Power = work / time; SI unit watt (W)

Light

• Reflection — angle of incidence = angle of reflection (plane mirror)
• Refraction — bending of light at the interface of two media; governed by Snell's law
• Lens — convex lens converges; concave lens diverges
• Human eye — cornea, iris, pupil, lens, retina; myopia (nearsighted) corrected by concave lens; hypermetropia (farsighted) corrected by convex lens

Electricity and Magnetism

• Ohm's law — V = IR (voltage = current × resistance)
• SI units: voltage volt (V), current ampere (A), resistance ohm (Ω)
• Magnetism — like poles repel, unlike poles attract; Earth acts as a magnet with magnetic north near geographic south
• Electromagnetic induction — a changing magnetic field induces a current (Faraday's law)

Heat and Temperature

• Heat is energy in transit; temperature measures the average kinetic energy of particles. Heat flows from hot to cold.
• SI unit of temperature is the kelvin (K); 0 °C = 273.15 K. Water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F) at sea level.
• Conduction (through solids, particle-to-particle), convection (bulk movement in fluids — a sea breeze), radiation (no medium needed — sunlight).
• Latent heat is the heat absorbed or released at a change of state with no temperature change. This is why a burn from steam is worse than from boiling water: condensing steam releases its latent heat of vaporisation into your skin.
• Anomalous expansion of water: water expands on cooling below 4 °C, so ice floats and lake water freezes top-down — the reason fish survive winter.

Sound

• Sound is a longitudinal mechanical wave and needs a material medium; it cannot travel through vacuum.
• Speed in air is about 343 m/s at 20 °C, roughly 1,500 m/s in water and about 5,000 m/s in steel — sound travels fastest in solids, slowest in gases.
• Frequency is measured in hertz (Hz). The audible range for humans is 20 Hz to 20,000 Hz; below is infrasonic, above is ultrasonic.
• Frequency determines pitch; amplitude determines loudness (measured in decibels).
• Echo is reflected sound; the ear distinguishes an echo only if the reflected sound arrives at least 0.1 s later, which needs a reflecting surface about 17 m away.
• Practical uses: SONAR measures ocean depth, and ultrasound is used in medical scanning and in cleaning.

Pressure, Density and Simple Machines

• Pressure = force / area; SI unit pascal (Pa). A sharp knife cuts better because the same force acts over a smaller area.
• Density = mass / volume (kg/m³). An object floats if its density is less than that of the fluid.
• Archimedes' principle: a body immersed in a fluid experiences an upthrust equal to the weight of the fluid displaced. This is why a ship of steel floats while a steel nail sinks.
• Pascal's law: pressure applied to an enclosed fluid is transmitted equally in all directions — the basis of the hydraulic brake and the hydraulic lift.
• Atmospheric pressure at sea level is about 101.3 kPa (760 mm of mercury), measured by a barometer; a falling barometer signals a storm.

Worked Examples the Exam Actually Sets

1. Power. A pump lifts 200 kg of water through 5 m in 20 s. Work = mgh = 200 × 10 × 5 = 10,000 J. Power = W/t = 10,000 / 20 = 500 W.

2. Ohm's law rearranged. A 60 W bulb runs on a 240 V supply. Current I = P/V = 60/240 = 0.25 A, and resistance R = V/I = 240/0.25 = 960 Ω.

3. Distance from an echo. An echo returns 2 s after a shout. The sound travelled there and back, so the one-way distance = (343 × 2)/2 = 343 m.

4. Electricity billing. A 1,000 W heater running 3 hours a day for 30 days consumes 1 × 3 × 30 = 90 kWh (90 units). This is exactly the arithmetic behind a Gruha Jyothi free-unit ceiling question.

Exam Discipline for Physics

Physics items are single-step. Write the formula, substitute, and check the unit — a wrong unit is the commonest way to lose a mark you had earned. Learn each quantity with its unit as one memory item (force–newton, work–joule, power–watt, pressure–pascal, frequency–hertz, resistance–ohm), and pair each law with one everyday example, because the paper frames roughly half of its physics questions as daily-life observations rather than as numbers.