IGCSE Physics 0625 Formula Sheet

Mechanics
Average speed (ms^-1) = distance (m) time (s)	s = d t
Average velocity (ms^-1) = displacement (m) time (s)	v = x t
Acceleration (ms^-2) = final velocity (ms^-1) - initial velocity (ms^-1) time (s)	a = v - u t
Weight (N) = mass (kg) × gravitational field strength (ms^-2) Earth's gravitational field strength = 9.8 ms^-2 (as of 2023)	W = mg
Force (N) = mass (kg) × acceleration (ms^-2)	F = ma
Density (kgm^-3) = mass (kg) volume (m³)	ρ = m V
Hooke's law: Force (N) = constant (Nm^-1) × extension (m)	F = kx
Pressure (Pa) = Force (N) area (m²)	P = F A
Fluid Pressure (Pa) = density (kgm^-3) × gravitational field strength (ms^-2 or Nkg^-1) × height (m)	P = ρgh
Work (J) = force (N) × distance moved (m)	W = Fd
Power (W) = work (J) time (s)	P = W t
Kinetic Energy (J) = ½ × mass (kg) × velocity² (ms^-1)	KE = ½mv²
Gravitational potential energy (J) = mass (kg) × gravitational field strength (ms^-2 or Nkg^-1) × height (m)	GPE = mgh
Efficiency (%) = useful power output (W or J) total power input (W or J) × 100%	η = P_out P_in × 100%
Moment (Nm) = Force (N) × perpendicular distance from pivot (m)	M = Fd
Sum of clockwise moments (Nm) = sum of anticlockwise moments (Nm)	F₁d₁ = F₂d₂
Momentum (kgms^-1) = mass (kg) × velocity (ms^-1)	p = mv
Impulsive Force (N) = change in momentum (kgms^-1) time (s)	F = Δp t
Impulse (kgms^-1 or Ns) = change in momentum (kgms^-1)	Δp = mv - mu

Thermal Physics
Boyle's Law for changes in gas pressure at constant temperature: pressure₁ (Pa) × volume₁ (m³) = pressure₂ (Pa) × volume₂ (m³)	P₁V₁ = P₂V₂
Energy (J) = mass (kg) × specific heat capacity (Jkg^-1°C^-1) × temperature change (°C)	Q = mcΔθ
Celsius to Kelvin: Temperature in Celsius (°C) = Temperature in Kelvin (K) - 273.15	C = K - 273.15

Waves
Wave speed (ms^-1) = frequency (Hz) × wavelength (m)	v = fλ
Frequency (Hz) = 1 Period (s)	f = 1 T
Refractive index = sine of the angle of incidence, i sine of the angle of refraction, r	n = sin i sin r
Refractive index = speed of light in vacuum speed of light in material	n = c v
Refractive index = 1 sine of critical angle	n = 1 sin c

Magnetism and Electricity
Current (A) = charge (C) time (s)	I = Q t
Voltage (V) = energy transferred (J) charge (C)	V = W Q
Voltage (V) = current (A) × resistance (Ω)	V = IR
Power (W) = current (A) × voltage (V)	P = IV
Power (W) = current² (A) × resistance (Ω)	P = I²R
Energy transferred (J) = current (A) × voltage (V) × time (s)	W = IVt
Energy transferred (J) = power (W) × time (s)	W = Pt
Resistors in series: Total Resistance (Ω) = sum of individual resistors (Ω)	R_total = R₁ + R₂ + R₃ ... + R_n
Resistors in parallel: 1 total resistance (Ω) = sum of individual resistors (Ω)	1 R_total = 1 R₁ + 1 R₂ + ... 1 R_n
Resistance (Ω) = resistivity (Ωm) × length (m) area (m²) Wires have a circular cross section, area = π × radius²	R = ρl A
Transformers: voltage in secondary coil (V) voltage in primary coil (V) = turns on secondary coil turns on primary coil	V_s V_p = N_s N_p
Transformers: voltage in secondary coil (V) voltage in primary coil (V) = current in primary coil (A) current in secondary coil (A)	V_s V_p = I_p I_s

Nuclear Physics
Alpha Decay: ²³⁸₉₂U → ²³⁴₉₀Th + ⁴₂He	^A_ZX → ^A-4_Z-2Y + ⁴₂He
Beta Decay: ²³⁴₉₀Th → ²³⁴₉₁Pa + ⁰_-1e	^A_ZX → ^A_Z+1Y + ⁰_-1e
Gamma Decay	^A_ZX → ^A_ZY + γ

Space Physics
Average orbital speed (ms^-1) = 2 × π × average radius of the orbit (m) orbital period (s)	v = 2πr T
distance of a far galaxy (m) speed away from us (ms^-1) = 1 Hubble Constant (s^-1) Hubble Constant is 2.2 × 10^-18 s^-1	d v = 1 H₀

IGCSE Physics (0625)

Formula Practice Questions & Step-by-Step Worked Solutions

Master Deck covering Mechanics, Thermal Physics, Waves, Electricity, Magnetism, Nuclear & Space Physics.

General Physics

Question 01 / 50

KEY FORMULA: Average Speed = Total Distance / Total Time

A car travels a distance of 450 m along a straight road in 15 s. Calculate its average speed in m/s.

Solution

Answer 01 / 50

Formula: Speed (s) = Distance (d) / Time (t) Calculation: s = 450 m / 15 s = 30 m/s

Final Answer: 30 m/s

General Physics

Question 02 / 44

KEY FORMULA: Velocity = Displacement / Time

An athlete runs with a displacement of 200 m due north in 25 s. Calculate the average velocity of the athlete in m/s.

Solution

Answer 02 / 44

Formula: Velocity (v) = Displacement (x) / Time (t) Calculation: v = 200 m / 25 s = 8 m/s (due north)

Final Answer: 8 m/s due north

General Physics

Question 03 / 44

KEY FORMULA: Acceleration = (v - u) / t

A cyclist increases their speed from 4 m/s to 10 m/s over a time period of 3 s. Calculate the acceleration in m/s².

Solution

Answer 03 / 44

Formula: a = (v - u) / t Given: u = 4 m/s, v = 10 m/s, t = 3 s a = (10 - 4) / 3 = 6 / 3 = 2 m/s²

Final Answer: 2 m/s²

Thermal Physics

Question 20 / 44

KEY FORMULA: Boyle's Law P₁V₁ = P₂V₂

A fixed mass of gas at constant temperature occupies a volume of 0.04 m³ at a pressure of 1.0 × 10⁵ Pa. If the volume is compressed to 0.01 m³, calculate the new gas pressure in Pa.

Solution

Answer 20 / 44

Formula: P₁V₁ = P₂V₂ Given: P₁ = 1.0 × 10⁵ Pa, V₁ = 0.04 m³, V₂ = 0.01 m³ (1.0 × 10⁵) × 0.04 = P₂ × 0.01 4000 = P₂ × 0.01 ⇒ P₂ = 400,000 Pa

Final Answer: 4.0 × 10⁵ Pa (400 kPa)

Properties of Waves

Question 23 / 44

KEY FORMULA: Wave Speed v = f × λ

A water wave has a frequency of 5 Hz and a wavelength of 0.4 m. Calculate the wave speed in m/s.

Solution

Answer 23 / 44

Formula: v = f × λ Given: f = 5 Hz, λ = 0.4 m v = 5 × 0.4 = 2.0 m/s

Final Answer: 2.0 m/s

Electricity

Question 30 / 44

KEY FORMULA: Ohm's Law V = I × R

Calculate the voltage across a resistor of 15 Ω when a current of 0.8 A flows through it.

Solution

Answer 30 / 44

Formula: V = I × R Given: I = 0.8 A, R = 15 Ω V = 0.8 × 15 = 12 V

Final Answer: 12 V

Nuclear Physics

Question 40 / 44

KEY CONCEPT: Mass number decreases by 4, Atomic number decreases by 2

Uranium-238 (²³⁸₉₂U) undergoes alpha decay to form Thorium (Th) and an alpha particle (⁴₂He). Write the balanced nuclear equation and state the mass number A and atomic number Z of Thorium.

Solution

Answer 40 / 44

Nuclear Equation: ²³⁸₉₂U → ᴬ_Z Th + ⁴₂He Mass Number Balance: 238 = A + 4 ⇒ A = 234 Atomic Number Balance: 92 = Z + 2 ⇒ Z = 90

Final Answer: A = 234, Z = 90 (²³⁴₉₀Th)

Space Physics

Question 50 / 50

KEY FORMULA: Hubble's Law v = H₀ × d

A distant galaxy is at a distance d = 4.0 × 10²⁴ m from Earth. Given the Hubble constant H₀ = 2.2 × 10⁻¹⁸ s⁻¹, calculate its recession velocity v in m/s.

Solution

Answer 50 / 50

Formula: v = H₀ × d Given: H₀ = 2.2 × 10⁻¹⁸ s⁻¹, d = 4.0 × 10²⁴ m v = (2.2 × 10⁻¹⁸) × (4.0 × 10²⁴) = 8.8 × 10⁶ m/s (8,800 km/s)

Final Answer: 8.8 × 10⁶ m/s (8800 km/s)

Complete

Practice Completed!

All formula practice problems and verified step-by-step solutions have been covered.
Review formulas and unit conversions regularly for exam success!