Pressure of a fixed mass of gas, P, is inversely proportional to the volume of the gas, V, when the temperature is held constant. P inversely proportional to V P = k/V , where k is a constant. PV = k With these concepts, you should be able to sketch the various graph. Do not memorise them. Use your concepts from Maths to help you to recall instead.

Transverse waves  are waves in which the  direction of the wave  is  perpendicular  to the direction of the vibration . e.g Light, water, and any waves in the electromagnetic spectrum Longitudinal waves  are waves in which the  direction of the wave  is  parallel  to the  direction of the vibration . e.g Sound (includes ultrasound or infrasound) Wave equation: V = fλ  In the videos below, the speed of wave is constant. Hence frequency is inversely proportional to wavelength.  [f increases, λ decreases, and vice versa]

Reflection of light using a mirror Refraction of light using various shaped optical mediums Total Internal Reflection (TIR) using a semi-circular perspex For Total Internal Reflection (TIR) to occur: 1) angle of incidence i is greater than the critical angle c 2) the light is travelling from an optically denser medium towards a less dense medium

High power electrical appliances are those which draws high current. The thinner the wire (smaller cross-sectional area), the higher the resistance of the cable which brings the current into the electrical appliances.   More thermal energy will be generated due to this higher resistance in the cable. The cable might be too hot or catch fire. So it is advisable to have thicker cables for high power electrical appliance as thicker cables have lower resistance.