(a) What is the principle upon which the lighting in fluorescent tubes operate?

(b) State two factors on which the colour of light from a fluorescent tube depends.

(a) List two types of waves, apart from light, that can be plane polarised

(b) State two applications of plane polarised light.

(a) State Hooke's law of elasticity

(b) A spiral spring, loaded with a piece of metal, extends by 10.5cm hair. When the metal is fully submerged in water, the spring extends by 6.8cm. Calculate the relative density of the metal. (Assume Hooke's law is obeyed).

(a) Explain electrolysis

(b) Classify the following substances as electrolytes and non-electrolytes: Sugar solution: paraffin, suit solution and grape fruit juice.

(a) State Heisenberg's uncertainty principle.

(b) Mention two phenomena that can only be explained in terms of the particulate nature of light.