Topic 1: Key concepts in physics

• What is the SI unit for length?

  Metre, m
• What is the SI unit for mass?

  Kilogram, kg
• What is the SI unit for time?

  Second, s
• What is the SI unit for electric current?

  Ampere, A
• What is the SI unit for temperature?

  Kelvin, K
• What is the SI unit for the amount of substance?

  Mole, mol
• What is the SI unit for electric potential difference?

  Volt, V
• What is the SI unit for frequency?

  Hertz, Hz
• What is the SI unit for force?

  Newton, N
• What is the SI unit for energy?

  Joule, J
• What is the SI unit for power?

  Watt, W
• What is the SI unit for pressure?

  Pascal, Pa
• What is the SI unit for electric charge?

  Coulomb, C
• What is the SI unit for electrical resistance?

  Ohm, Ω
• What is the SI unit for magnetic flux density?

  Tesla, T
• What are the prefixes for the following SI units: giga, mega, kilo, centi, milli, micro, and nano?

  • Giga (G): x \(10^9\) (1 billion)
  • Mega (M): x \(10^6\) (1 million)
  • Kilo (k): x \(10^3\) (1 thousand)
  • Centi (c): x \(10^{-2}\) (1 hundredth)
  • Milli (m): x \(10^{-3}\) (1 thousandth)
  • Micro (µ): x \(10^{-6}\) (1 millionth)
  • Nano (n): x \(10^{-9}\) (1 billionth)
• What is the equation for calculating distance?

  Distance = speed × time
• What does the equation \( a = \frac{v - u}{t} \) represent?

  It represents acceleration as the change in velocity over time.
• What does the equation \( F = ma \) represent?

  It represents the relationship between force, mass, and acceleration.
• What is the equation for weight?

  Weight = mg
• What does the equation \( \Delta GPE = mg\Delta h \) calculate?

  It calculates the change in gravitational potential energy.
• What is the equation for kinetic energy?

  KE = \frac{1}{2} mv^2
• What is the formula for efficiency?

  Efficiency = \frac{\text{useful energy output}}{\text{total energy input}}
• What is the equation for wave speed?

  Wave speed = \( v = f\lambda \)
• What is the equation for work done?

  Work done = force × distance (moved in the direction of the force) = \( E = Fd \)
• What is the formula for power?

  Power = \frac{\text{work done}}{\text{time}} = \frac{\text{energy transferred}}{\text{time taken}}
• What is the equation for the moment of force?

  Moment of force = force × perpendicular distance
• What does the equation \( E = QV \) represent?

  It represents energy transferred as charge moved times potential difference.
• What is the equation for charge?

  Charge = current × time = \( Q = It \)
• What is the equation for voltage?

  Voltage = Current × Resistance = \( V = IR \)
• What is the equation for electrical power?

  Electrical Power = current × pd = \( P = IV \)
• What is the alternative equation for electrical power?

  Electrical power = current² × resistance = \( P = I^2R \)
• What is the equation for density?

  Density = \frac{\text{mass}}{\text{volume}} = \rho = \frac{m}{V}
• What is the equation for the force on a spring?

  Force on spring = spring constant × extension = \( F = k\Delta x \)
• What is the equation for pressure?

  Pressure = \frac{\text{force}}{\text{area}} = P = \frac{F}{A}
• What are the equations given for energy transferred in electrical systems?

  1. \( \text{energy transferred} = IVt \)

  2. \( \frac{pd \text{ across primary}}{pd \text{ across secondary}} = \frac{\text{number of turns in primary}}{\text{number of turns in secondary}} \)

  3. \( P_p = P_s = V_p \times I_p = V_s \times I_s \)
• What is the equation for change in energy?

  Change in energy = mass × specific heat capacity × temperature change = \( \Delta Q = mc\Delta \theta \)
• What is the equation for energy in terms of specific latent heat?

  Energy = mass × specific latent heat = \( Q = ml \)
• What is the equation for pressure and volume change?

  Pressure and volume change = \( P_1V_1 = P_2V_2 \)
• What is the equation for energy transferred in a spring?

  Energy transferred = \frac{1}{2} k(\Delta x)^2