(a) List two examples each of substances with:

(i) low viscosity;

(ii) high viscosity.

(b) When is a liquid said to be viscostatic?

State one reason each why cathode rays:

(a) are not electromagnetic waves;

(b) cast sharp shadows of objects in their path;

(c) can rotate a light paddle wheel inside a discharge tube.

 An X-ray tube operates at a potential of 2500 V. If the power of the tube is 750 W, calculate the speed of the electron striking the target. [e = 1.6 x 10\(^{-19}\) C; mass of electron = 9.1 x 10\(^{-3}\) kg]

(a) Write down the names of two particles used in explaining the wave nature of matter.

(b) State the wave characteristics which are exhibited by the particles named in (a) above.

 (s) State the Heisenberg Uncertainty Principle.
(b) The product of the uncertainties in Heisenberg Uncertainty Principle is equal to or greater than a constant. State the mathematical expression for this constant.