UAE TLS Physics Subject Test flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Newton's second law

The net force on a body equals its mass times its acceleration (F = ma); acceleration is in the direction of the net force.

Conservation of momentum

In an isolated system the total momentum before a collision equals the total momentum after, regardless of whether the collision is elastic or inelastic.

Centripetal acceleration

An object moving in a circle at constant speed accelerates toward the centre with magnitude v²/r, because its velocity direction changes continuously.

Work-energy theorem

The net work done on an object equals the change in its kinetic energy, linking force and displacement to speed changes.

Projectile motion components

Horizontal velocity stays constant while vertical velocity changes by g each second; the two components are independent and combine as vectors.

Wave equation

Wave speed equals frequency multiplied by wavelength (v = fλ); frequency is fixed by the source, so wavelength changes when speed changes.

Snell's law

At a boundary, n₁ sin θ₁ = n₂ sin θ₂; light bends toward the normal when entering a medium of higher refractive index.

Total internal reflection

Occurs when light in a denser medium strikes a boundary beyond the critical angle, so no light refracts out and all is reflected internally.

Doppler effect

The observed frequency of a wave shifts upward when source and observer approach and downward when they recede, due to relative motion.

Standing wave nodes

Points of zero displacement in a standing wave; on a string fixed at both ends, nodes occur at the ends and the fundamental wavelength is twice the length.

Ohm's law

For an ohmic conductor at constant temperature, current is proportional to voltage (V = IR); resistance is the constant of proportionality.

Parallel circuit rule

Components in parallel share the same voltage; the reciprocal of total resistance equals the sum of the reciprocals of individual resistances.

Faraday's law

A changing magnetic flux through a circuit induces an emf proportional to the rate of change of flux linkage; Lenz's law fixes its direction.

Magnetic force on charge

A moving charge experiences force F = qvB sin θ, perpendicular to both its velocity and the magnetic field; a charge at rest feels none.

Electrical power

Power dissipated in a component is P = VI, equivalently I²R or V²/R, measured in watts for a resistive load.

Ideal gas law

PV = nRT relates pressure, volume, amount in moles and absolute temperature; temperature must be expressed in kelvin.

First law of thermodynamics

The change in internal energy equals heat added to the system minus work done by the system (ΔU = Q − W).

Specific latent heat

The energy per unit mass needed to change phase at constant temperature, Q = mL; no temperature change occurs during the transition.

Kinetic theory of gases

Gas pressure arises from molecular collisions with the walls; average molecular kinetic energy is proportional to absolute temperature.

Second law of thermodynamics

Heat flows spontaneously from hotter to colder bodies, and the entropy of an isolated system never decreases in any real process.

Photoelectric threshold frequency

Below a minimum frequency, no electrons are emitted regardless of light intensity, because each photon lacks the energy to overcome the work function.

Photoelectric equation

Maximum photoelectron kinetic energy equals photon energy minus work function: KEmax = hf − φ, with φ characteristic of the metal.

De Broglie wavelength

Every particle has an associated wavelength λ = h/p; it becomes measurable only for very small masses or low momenta.

Radioactive half-life

The time for half the nuclei in a sample to decay; after n half-lives the fraction remaining is one half raised to n.

Atomic line spectra

Sharp emission or absorption lines occur at wavelengths matching electron transitions between discrete atomic energy levels, acting as an atomic fingerprint.

Accuracy versus precision

Accuracy is closeness to the true value; precision is closeness of repeated readings to each other. A measurement can be precise but inaccurate.

Combining percentage uncertainties

For multiplication or division, add the percentage uncertainties of the input quantities; for addition or subtraction, add absolute uncertainties.

Random versus systematic error

Random errors scatter readings both ways and average out; systematic errors shift all readings in one direction and are not removed by averaging.

Falsifiable hypothesis

A scientific hypothesis must make a testable prediction that could be shown false by observation or experiment.

Graph gradient meaning

The slope of a straight-line graph gives the rate of change of the y-variable with respect to the x-variable, with units of y divided by x.

Formative versus summative assessment

Formative assessment is ongoing and used to adjust teaching; summative assessment judges achievement at the end of a unit or course.

Eliciting prior conceptions

Before teaching, teachers probe students' existing ideas, since new learning builds on prior understanding and misconceptions must be surfaced to be changed.

Inquiry-based practical sequence

Students predict, plan and carry out an investigation, collect and analyse data, then construct and communicate an evidence-based explanation.