NTS NAT-ICS Physics Syllabus

Define linear momentum and give its formula and SI unit.

Momentum is the product of mass and velocity: p = mv. It is a vector with SI unit kg·m/s.

State the law of conservation of momentum.

In the absence of an external net force, the total momentum of a system before collision equals the total momentum after collision.

Distinguish between elastic and inelastic collisions.

In an elastic collision both momentum and kinetic energy are conserved. In an inelastic collision momentum is conserved but kinetic energy is not (some converts to heat/sound/deformation).

Define impulse and state its relation to momentum.

Impulse = force × time (Ft) and equals the change in momentum: Ft = Δp = mv − mu. SI unit is N·s (= kg·m/s).

Define Simple Harmonic Motion (SHM).

SHM is oscillatory motion in which the restoring force (or acceleration) is directly proportional to displacement from the equilibrium position and directed toward it: a ∝ −x.

Give the formula for the time period of a simple pendulum.

T = 2π√(L/g), where L is the length and g is gravitational acceleration. Period is independent of mass and amplitude (for small swings).

Define frequency and period, and give the relation between them.

Frequency f is the number of oscillations per second (unit hertz, Hz); period T is the time for one oscillation. They are reciprocals: f = 1/T.

Give the formula for the time period of a mass on a spring in SHM.

T = 2π√(m/k), where m is the mass and k is the spring constant.

Distinguish between transverse and longitudinal waves with an example of each.

In a transverse wave the medium vibrates perpendicular to wave travel (e.g., light, water waves). In a longitudinal wave it vibrates parallel to wave travel (e.g., sound waves).

State the wave equation relating speed, frequency and wavelength.

v = fλ, where v = wave speed, f = frequency, λ = wavelength.

Define wavelength and amplitude of a wave.

Wavelength is the distance between two consecutive points in phase (e.g., crest to crest). Amplitude is the maximum displacement of a particle from its equilibrium position.

What is the difference between constructive and destructive interference?

Constructive interference occurs when waves meet in phase, producing larger amplitude. Destructive interference occurs when waves meet out of phase (antiphase), reducing or cancelling amplitude.

Name the property of sound that corresponds to frequency and the one that corresponds to amplitude.

Frequency determines pitch (high frequency = high pitch); amplitude determines loudness (greater amplitude = louder sound).

What is the approximate speed of sound in air at room temperature, and why can't sound travel through a vacuum?

About 340 m/s in air at ~20°C. Sound needs a material medium to transmit vibrations, so it cannot travel through a vacuum.

Define an echo and the condition for it to be heard distinctly.

An echo is sound reflected back to the listener. It is heard distinctly when the reflected sound returns after at least about 0.1 s (reflector roughly ≥17 m away).

State the Doppler effect.

The Doppler effect is the apparent change in frequency (pitch) of a wave due to relative motion between the source and the observer; frequency rises as they approach and falls as they recede.

Differentiate between heat and temperature.

Heat is the total thermal energy transferred between bodies due to temperature difference (unit joule). Temperature is a measure of the average kinetic energy of particles (unit kelvin/°C).

Convert a temperature from Celsius to Kelvin and give absolute zero in both scales.

K = °C + 273 (more precisely 273.15). Absolute zero = 0 K = −273°C.

Name the three modes of heat transfer.

Conduction, convection, and radiation.

Define specific heat capacity and give the heat formula.

Specific heat capacity is the heat needed to raise 1 kg of a substance by 1 K (unit J/kg·K). Heat: Q = mcΔT, where m is mass, c is specific heat, ΔT is temperature change.

Define latent heat of fusion and latent heat of vaporization.

Latent heat of fusion is the heat needed to change unit mass of a solid to liquid at its melting point; latent heat of vaporization is the heat to change unit mass of liquid to gas at its boiling point — both at constant temperature.

State the First Law of Thermodynamics.

Energy is conserved: the heat added to a system equals the increase in internal energy plus the work done by the system: Q = ΔU + W.

State the Second Law of Thermodynamics (one common statement).

Heat cannot spontaneously flow from a colder body to a hotter body; the entropy (disorder) of an isolated system tends to increase.

State Boyle's Law and its formula.

At constant temperature, the pressure of a fixed mass of gas is inversely proportional to its volume: P ∝ 1/V, or P₁V₁ = P₂V₂.

State Charles's Law and its formula.

At constant pressure, the volume of a fixed mass of gas is directly proportional to its absolute (Kelvin) temperature: V ∝ T, or V₁/T₁ = V₂/T₂.

Write the ideal gas equation and identify each term.

PV = nRT, where P = pressure, V = volume, n = number of moles, R = universal gas constant (8.31 J/mol·K), T = absolute temperature.

State Coulomb's Law and its formula.

The force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them: F = kq₁q₂/r², where k ≈ 9×10⁹ N·m²/C².

Define electric field intensity and give its formula and unit.

Electric field intensity is the force per unit positive charge at a point: E = F/q. Its SI unit is N/C (or V/m); it is a vector pointing away from positive charges.

State Ohm's Law and its formula, and give the unit of resistance.

At constant temperature, the current through a conductor is directly proportional to the voltage across it: V = IR. Resistance is measured in ohms (Ω).

Give the formulas for total resistance of resistors in series and in parallel.

Series: R = R₁ + R₂ + R₃ + … In parallel: 1/R = 1/R₁ + 1/R₂ + 1/R₃ + …