OAT (Optometry Admission Test) Physics Syllabus

State the law of conservation of momentum.

In the absence of a net external force, the total momentum of a system is conserved: Σp_before = Σp_after.

Compare elastic and inelastic collisions.

Both conserve momentum. Elastic collisions also conserve kinetic energy. In perfectly inelastic collisions the objects stick together and the maximum kinetic energy is lost.

What is the definition of density, and the formula for pressure in a fluid?

Density ρ = m/V. Pressure P = F/A. SI unit of pressure is the pascal (Pa = N/m²).

What is the formula for hydrostatic (gauge) pressure at depth h in a fluid?

P = ρgh (gauge pressure). Absolute pressure = P_atmospheric + ρgh.

State Pascal's principle.

A pressure change applied to an enclosed fluid is transmitted undiminished to every part of the fluid and the walls of the container (the basis of hydraulic lifts).

State Archimedes' principle and the buoyant force formula.

The buoyant force on a submerged or floating object equals the weight of the fluid displaced: F_b = ρ_fluid V_displaced g.

State the continuity equation for incompressible fluid flow.

A1v1 = A2v2 (volume flow rate is constant). Where the cross-sectional area decreases, the fluid speed increases.

State Bernoulli's equation.

P + ½ρv² + ρgh = constant along a streamline. Higher fluid speed corresponds to lower pressure.

Convert between Celsius, Kelvin, and Fahrenheit.

K = °C + 273.15; °F = (9/5)°C + 32; °C = (5/9)(°F − 32).

What is the equation for heat transfer that raises temperature (specific heat)?

Q = mcΔT, where c is the specific heat capacity. For phase changes (no temperature change): Q = mL (L = latent heat).

State the ideal gas law.

PV = nRT, where R = 8.314 J/(mol·K). Equivalently PV = NkT, with k = Boltzmann's constant = 1.38×10⁻²³ J/K.

State the first law of thermodynamics.

ΔU = Q − W: the change in internal energy equals heat added to the system minus work done by the system. (Sign conventions may vary.)

State the second law of thermodynamics (entropy form).

The total entropy of an isolated system never decreases; heat flows spontaneously from hot to cold, and no process is 100% efficient at converting heat to work.

What is the relationship between wave speed, frequency, and wavelength?

v = fλ. Frequency f = 1/T, where T is the period.

Compare transverse and longitudinal waves with examples.

Transverse: oscillations are perpendicular to wave travel (e.g., light, waves on a string). Longitudinal: oscillations are parallel to wave travel (e.g., sound).

What is the Doppler effect for sound (qualitatively)?

Observed frequency increases when source and observer approach each other and decreases when they move apart, due to compression/stretching of wavelengths.

What conditions produce constructive and destructive interference?

Constructive: path difference = nλ (waves in phase, amplitudes add). Destructive: path difference = (n + ½)λ (waves out of phase, amplitudes cancel).

How is sound intensity level in decibels calculated?

β = 10 log10(I/I0), where I0 = 10⁻¹² W/m² (threshold of hearing). Every 10 dB corresponds to a 10× change in intensity.

What is the restoring force in simple harmonic motion (Hooke's law)?

F = −kx: the restoring force is proportional to displacement and directed opposite to it.

What is the period of a mass on a spring versus a simple pendulum?

Mass-spring: T = 2π√(m/k). Simple pendulum: T = 2π√(L/g) (small-angle approximation).

State Coulomb's law for the force between two point charges.

F = k q1 q2 / r², where k ≈ 8.99×10⁹ N·m²/C². Like charges repel; opposite charges attract.

What is the electric field due to a point charge, and the force on a charge in a field?

E = kq/r² (field of a point charge); F = qE (force on charge q in field E). Field points away from positive, toward negative charges.

Define electric potential (voltage) and relate it to potential energy.

Potential V = U/q = kQ/r for a point charge. Potential energy U = qV. Unit: volt (V = J/C).

State Ohm's law and the formula for electrical power.

V = IR. Power P = IV = I²R = V²/R. Resistance unit: ohm (Ω).

How do resistors combine in series versus in parallel?

Series: R_total = R1 + R2 + … Parallel: 1/R_total = 1/R1 + 1/R2 + … (series resistances add; parallel total is less than the smallest).

How do capacitors combine in series versus parallel, and what is stored energy?

Parallel: C_total = C1 + C2 + … Series: 1/C_total = 1/C1 + 1/C2 + … Energy stored: U = ½CV². Capacitance C = Q/V.

What is the magnetic force on a moving charge and on a current-carrying wire?

On a charge: F = qvB sin θ. On a wire: F = BIL sin θ. Direction given by the right-hand rule.

State Faraday's law of electromagnetic induction and Lenz's law.

Faraday: induced EMF = −dΦ/dt (rate of change of magnetic flux). Lenz: the induced current opposes the change in flux that produced it (the minus sign).

State Snell's law of refraction and define index of refraction.

n1 sin θ1 = n2 sin θ2. Index of refraction n = c/v (speed of light in vacuum divided by speed in the medium); n ≥ 1.

What is the thin lens / mirror equation and the magnification formula?

1/f = 1/do + 1/di. Magnification m = −di/do = hi/ho. Positive di means a real image; negative means virtual.

Distinguish converging and diverging lenses by focal length and image type.

Converging (convex) lens: f > 0, can form real inverted or virtual upright images. Diverging (concave) lens: f < 0, always forms a virtual, upright, reduced image.

What is the condition for total internal reflection and the critical angle?

Occurs when light travels from a higher to a lower index medium at an angle exceeding the critical angle θc, where sin θc = n2/n1 (n1 > n2).

List the SI base units for length, mass, time, current, and temperature.

Length: meter (m); mass: kilogram (kg); time: second (s); electric current: ampere (A); temperature: kelvin (K).

What do the metric prefixes nano, micro, milli, kilo, mega, and giga represent?

nano = 10⁻⁹, micro = 10⁻⁶, milli = 10⁻³, kilo = 10³, mega = 10⁶, giga = 10⁹.

What is the photoelectric effect and the photon energy equation?

Light striking a metal ejects electrons only if photon energy exceeds the work function. Photon energy E = hf = hc/λ, where h = 6.63×10⁻³⁴ J·s.

State the mass-energy equivalence and the basics of radioactive half-life.

E = mc². Half-life is the time for half of a radioactive sample to decay; after n half-lives, the remaining fraction is (½)ⁿ.

What is dimensional analysis and why is it useful in problem solving?

It tracks units through a calculation to check that an equation is consistent and to convert units. If the units of the result are wrong, the setup is wrong.

Compare scalar and vector quantities with examples.

Scalars have magnitude only (e.g., mass, time, speed, energy, temperature). Vectors have magnitude and direction (e.g., displacement, velocity, acceleration, force).

How do you add two perpendicular vectors to find the resultant magnitude and direction?

Magnitude: R = √(Rx² + Ry²) (Pythagorean theorem). Direction: θ = tan⁻¹(Ry/Rx).