Physics

• Define the ohm

  Volt over ampere
• Define the coulomb

  Amperes x seconds
• What is a potentiometer?

  A continuously variable potential divider
• What is Kirchoffs first law a consequence of ?

  Charge
• What is Kirchhoff second law a consequence of?

  Energy
• Define Kirchhoff‘s first law

  The sum of the currents entering a junction is the sum of the currents leaving the junction
• Define Kirchhoff’s second law

  The sum of the EMFs in a closed circuit is equal to the sum of the potential differences
• Define TERMINAL potential difference

  Potential difference between terminals of cell when current is delivered
• Define Ohm‘s law

  For a conductor, at constant temperature, the current in the conductor is proportional to the potential difference across it
• Define charge

  Current x time
• Define “quantised”

  Only exists in integer multiples of the charge on an electron
• Define coherence

  When two waves have the same frequency and a constant phase difference
• Define destructive interference

  Peaks of 1 wave line up with the troughs on the other wave
• Define constructive interference

  The peaks and troughs line up on both waves (are in phase)
• Define Diffraction

  The spreading out of waves when they pass an obstruction
• What is the principle of superposition?

  When 2 or more waves meet at a point, the resultant displacement is the sum of the individual wave displacements
• What is a longitudinal wave?

  Vibrations of the particles in the wave are parallel to the direction of wave travel
• What is a transverse wave?

  Vibrations of the particles in the wave are perpendicular to the direction of the wave travel
• Define intensity

  Power per unit area
• Define frequency

  The number of complete wave oscillations per unit time
• Define period

  The time taken for 1 complete oscillation
• Define wavelength

  The minimum distance between particles, vibrating in phase
• Define amplitude

  The maximum displacement of a wave
• Define plastic deformation

  Object does not return to the original length
• Define elastic deformation

  Object returns to original length
• Define Young’s modulus

  Stress over strain
• Define stress

  Force over area
• Define limit of proportionality

  The point beyond which the extension is not proportional to the force
• Define tensile forces

  Causes an Increase in length (extension)
• Define power

  Work done per unit time
• Define work done

  Product of the force and displacement, in the direction of the force
• Define Upthrust

  The weight of the liquid displaced
• Define pressure

  Force per unit area
• Define density

  Mass per unit volume
• Define the principle of moments

  The sum of the anticlockwise moments are equal to the sum of the clockwise moments
• Define Torque

  The resulting moment of a couple
• Define couple

  A pair of forces which produces rotation only
• Define moment

  Product of the force and the perpendicular distance
• Define centre of gravity

  The point where all the weight of an object acts
• Define force

  Rate of change of momentum