All physics practicals

• What is an independent variable in an experiment?

  The variable that is changed
• What is a dependent variable in an experiment?

  The variable that changes as a result
• Why are control variables important in experiments?

  They ensure results are accurate
• What should you always state when measuring?

  The equipment used for each measurement
• How can you reduce parallax error when measuring?

  Align your eye with the measurement
• Why is it important to take multiple measurements?

  To calculate a mean and reduce errors
• What format is recommended for writing answers in practicals?

  Bullet point format
• What is specific heat capacity (SHC)?

  Energy needed to raise 1 kg by 1°C
• How can you find the SHC of water or metals?

  Using an electrical heater in a beaker
• What is the equation for specific heat capacity?

  SHC = energy / (mass × temperature change)
• How do you calculate energy supplied to the block?

  Multiply power by time in seconds
• What does a graph of resistance against length show?

  A directly proportional relationship
• What is Ohm's law equation?

  Resistance = voltage / current
• What happens to the resistance of a filament bulb at higher currents?

  Resistance increases with higher currents
• How do diodes behave in terms of current flow?

  Allow current to flow in one direction
• How do you find the density of a solid object?

  Measure mass and calculate volume
• How do you find the density of an irregular object?

  Use water displacement method
• What is the density of pure water?

  1 g/cm³
• How do you find the spring constant?

  Plot force against extension
• What does Hooke's law state?

  Force is proportional to extension
• How do you verify Newton's Second Law?

  Attach masses to a trolley on a track
• What is the wave equation?

  V = F × λ
• How do you measure wavelength using a ripple tank?

  Measure length of 10 waves and divide
• What is the best emitter of infrared radiation?

  Matte black surfaces
• How do you find the refractive index of a material?

  Calculate sin(i) / sin(r)
• What are the steps to measure specific heat capacity?

  1. Insert heater into water or metal block
  2. Measure mass and initial temperature
  3. Turn on heater and measure temperature at intervals
  4. Measure current and voltage to calculate power
  5. Use SHC equation to find specific heat capacity
• What are the key components of the resistance of a wire experiment?

  • Use constantan wire
  • Attach wires with crocodile clips
  • Measure current and voltage
  • Change length of wire
  • Calculate resistance using Ohm's law
• What are the characteristics of IV graphs for different components?

  • Fixed resistor: straight line through origin
  • Filament bulb: curve, resistance increases with current
  • Diode: current flows only in one direction
• What are the methods to find density of liquids and solids?

  • Solids: measure mass and volume, use displacement for irregular shapes
  • Liquids: measure mass using a balance, measure volume with a measuring cylinder
• What are the steps to verify Newton's Second Law?

  1. Attach slotted masses to a trolley
  2. Measure acceleration using light gates or stop clock
  3. Change force by adjusting masses
  4. Plot force against acceleration
• What are the methods to measure wave speed?

  • Use ripple tank and measure wavelength and frequency
  • Use stationary waves on a string and calculate wave speed
• What are the effects of surface types on infrared absorption?

  • Matte black: best emitter and absorber
  • Shiny surfaces: worst emitter and absorber
• What are the steps to find the refractive index using a glass block?

  1. Shine light at an angle
  2. Measure angles of incidence and refraction
  3. Calculate sin(i) / sin(r) for multiple angles