MOJZA O Levels & IGCSE Physics (5054 & 0625) Review Flashcards

Compendium of practice questions and answers covering standard O Level and IGCSE Physics topics including mechanics, thermal energy, wave properties, electricity, radioactivity, and space physics.

What is the precision of a micrometre screw gauge?

It can be used for measuring up to $0.01\,mm$.

What are the SI base units for mass, length, time, current, and temperature?

Mass: Kilogram $(kg)$, Length: Metre $(m)$, Time: Second $(s)$, Current: Ampere $(A)$, Temperature: Kelvin $(K)$.

How is the period of a pendulum defined and accurately measured?

The period is the time taken for one complete oscillation; it should be measured by recording the total time for around $20$ oscillations and taking the average.

What is the formula for calculating the volume of an irregular object using displacement?

$\text{Volume of irregular object} = \text{Final volume} - \text{Initial volume}$.

Distinguish between scalar and vector quantities.

Scalars have only magnitude (e.g., distance, speed, time, mass, energy, temperature), while vectors have both magnitude and direction (e.g., displacement, velocity, acceleration, force, weight, momentum).

State Pythagoras' Theorem and the Trigonometric ratios used for vector calculations.

$c^2 = a^2 + b^2$, $\sin(\theta) = \frac{\text{Opposite}}{\text{Hypotenuse}}$, $\cos(\theta) = \frac{\text{Adjacent}}{\text{Hypotenuse}}$, $\tan(\theta) = \frac{\text{Opposite}}{\text{Adjacent}}$.

What does the gradient represent in distance-time and speed-time graphs?

In a distance-time graph, the gradient represents speed. In a speed-time graph, the gradient represents acceleration.

What is the acceleration of an object in free fall near the surface of the Earth?

A constant acceleration of $9.8\,m/s^2$, represented by the symbol $g$.

Define weight and state its formula.

Weight is the force of gravity acting on a mass, calculated as $W = mg$, where $g$ is approximately $10\,N/kg$ (or $9.8\,N/kg$) and measured in Newtons $(N)$.

What is the formula for density ($\rho$)?

$\rho = \frac{m}{V}$ (Mass per unit volume).

State Newton’s Three Laws of Motion.

1st: Objects remain at rest or uniform motion unless a resultant force acts. 2nd: $F = ma$. 3rd: Every action has an equal and opposite reaction ($F_1 = F_2$).

What is Hooke’s Law and its limit?

$\text{Force} = \text{Spring constant} \times \text{Extension}$ ($F = kx$); it applies only until the limit of proportionality is reached.

Define momentum and the principle of its conservation.

Momentum $p = mv$; total momentum remains constant in a collision if no external forces act.

How is work done calculated?

$\text{Work} = \text{Force} \times \text{Distance travelled}$; measured in Joules $(J)$ or Newton Metres $(Nm)$.

What are the formulas for Gravitational Potential Energy ($GPE$) and Kinetic Energy ($KE$)?

$GPE = mgh$ (mass $\times$ gravity $\times$ height) and $KE = \frac{1}{2}mv^2$.

Define power and its unit.

Power is the rate of transfer of energy or rate of doing work ($P = \frac{\text{Work}}{\text{Time}}$), measured in Watts $(W)$ or Joules per second.

State the formula for pressure and liquid pressure.

$\text{Pressure} = \frac{\text{Force}}{\text{Area}}$ and $\text{Liquid Pressure} = \rho gh$ (density $\times$ gravity $\times$ depth).

Define absolute zero in Celsius.

$-273\,^\circ C$, the temperature at which matter possesses no kinetic energy.

What is Boyle's Law?

For a fixed mass at a constant temperature, $p_1V_1 = p_2V_2$.

Define Specific Heat Capacity and its formula.

The energy required per unit mass per unit temperature change; $Q = mc\Delta T$.

Identify the three thermal transfer processes and their primary mediums.

Conduction (solids), Convection (fluids: liquids and gases), and Radiation (vacuum/infrared waves).

What are the two types of waves and their particle vibrations?

Transverse (vibration perpendicular to wave travel, e.g., light) and Longitudinal (vibration parallel to wave travel, e.g., sound).

State the Universal Wave Equation.

$v = f\lambda$ (Wave speed = frequency $\times$ wavelength).

What is Snell's Law and the refractive index formula?

$n_1\sin(\theta_1) = n_2\sin(\theta_2)$ and $n = \frac{\sin(i)}{\sin(r)}$.

What is the speed of all electromagnetic waves in a vacuum?

$3 \times 10^8\,m/s$.

Identify the components of the EM spectrum in order of increasing frequency.

Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays.

What is the human audible frequency range?

$20\,Hz$ to $20\,000\,Hz$.

Distinguish between hard and soft magnetic materials.

Soft magnetic materials (e.g., iron) are easy to magnetize/demagnetize and used for electromagnets; hard magnetic materials (e.g., steel) are hard to demagnetize and used for permanent magnets.

Define Current, Potential Difference, and Ohm's Law.

$\text{Current} \, (I = \frac{Q}{t})$ is the rate of flow of charge. $\text{Potential Difference} \, (V)$ is energy per Coulomb. $\text{Ohm's Law}: V = IR$.

How do resistance rules differ for series and parallel circuits?

Series: $R_{\text{total}} = R_1 + R_2 ...$. Parallel: $\frac{1}{R_{\text{total}}} = \frac{1}{R_1} + \frac{1}{R_2} ...$.

State the function of a step-up and step-down transformer.

Step-up increases voltage and decreases current; step-down decreases voltage and increases current based on the ratio $\frac{V_p}{V_s} = \frac{N_p}{N_s}$.

List the three types of nuclear radiation and their properties.

Alpha ($+2$ charge, helium nucleus, stopped by paper), Beta ($-1$ charge, electron, stopped by aluminium), and Gamma ($0$ charge, EM wave, reduced by lead).

Define half-life.

The time taken for the number of atoms (or activity) of a radioactive isotope to half.

What is the age of the universe according to the Big Bang Theory and Hubble's Constant?

Approximately $14$ billion years; age is estimated by $\frac{1}{H_0}$ where $H_0 = 2.2 \times 10^{-18}\,\text{s}^{-1}$.

State Hubble's Law.

$v = H_0 \times d$ (Recessional velocity = Hubble's constant $\times$ distance).