Physics Class 10: Motion and Energy

Motion

• Speed: Rate of change of distance over time.
• Velocity: Rate of change of displacement over time, including direction.
• Acceleration: Rate of change of velocity (a = Δv/t).
• Distance-Time Graphs: Gradient represents speed.
• Velocity-Time Graphs: Gradient represents acceleration; area represents distance.

Work, Energy, and Power

• Work: Energy transferred when a force moves an object (W = Fd).
• Kinetic Energy: KE = ½mv².
• Power: Rate of doing work (P = E/t).

Electricity

• Current: Rate of charge flow (I = Q/t).
• Voltage: Energy per unit charge (V = E/Q).
• Resistance: Opposition to current (R = V/I).
• Ohm's Law: V ∝ I (at constant temperature).

Electromagnetic Effects

• Magnetic Field: Region of magnetic force.
• Induction: Current produced by a moving conductor in a magnetic field.
• Transformer: Vp/Vs = Np/Ns.

Waves

• Wavelength: Distance between wave crests.
• Frequency: Number of waves per second (f = 1/T).
• Refraction: Bending of waves at a boundary.

Thermal Physics

• Specific Heat Capacity: Heat to raise 1 kg by 1°C (Q = mcΔT).
• Conduction/Convection/Radiation: Methods of heat transfer.

Radioactivity

• Decay: Release of alpha, beta, or gamma radiation.
• Half-life: Time for half the nuclei to decay.
• Alpha: Low penetration, ⁴₂He.
• Gamma: High penetration EM wave.

Measurement Techniques

• Micrometer Screw Gauge: Measures small lengths (e.g., wire diameter) to ±0.01 mm.
• Vernier Calipers: Measures internal/external diameters to ±0.1 mm.
• Metre Rule: Measures lengths to ±1 mm.
• Stopwatch: Measures time with reaction error (~0.2 s).
• Digital Meters: Reduce parallax errors.

Errors and Accuracy

• Random Errors: Caused by observer variation; reduced with multiple readings.
• Systematic Errors: Caused by instrument calibration issues; reduced by zero correction.
• Parallax Error: Avoided by reading at eye level.
• Significant Figures: Reflect instrument precision.

Graphical Analysis

• Best-Fit Line: Balanced line, minimizing point deviations above and below.
• Gradient Calculation: Use largest possible triangle for accuracy.
• Intercepts: Help derive equations from graphs.
• Direct Proportionality: Straight line through the origin.

Light and Optics

• Ray Diagrams: Use arrows to show light direction.
• Refraction: Use protractor for accurate angle measurements.
• Lenses: Focal length is determined using 1/f = 1/u + 1/v.
• Critical Angle: Determined using sin c = 1/n.

Electricity Experiments

• Ohm's Law: Plot V vs I; gradient = Resistance (R = V/I).
• Series Circuit: Same current, sum of voltages.
• Parallel Circuit: Same voltage, sum of currents.
• Resistor Heating: Causes increase in resistance.

Heat and Temperature

• Thermometer Calibration: Ice (0°C), Steam (100°C).
• Specific Heat Capacity: Use Q = mcΔT; ensure proper insulation.
• Cooling Curves: Monitor temperature drop over time.

Motion and Forces

• Trolley on Ramp: Use light gates to measure acceleration.
• Pendulum: Measure time for 10 oscillations then divide for T.
• Forces and Moments: Ensure perpendicular distance in torque calculations.

Waves

• Ripple Tank: Measures wavelength using strobe light.
• Speed of Sound: Measure echo timing.
• Resonance: Vibrating air column with tuning fork.