An electron moves with a speed of 2.00 x 10\(^7\) ms\(^{-1}\) in an orbit in a uniform magnetic field of 1.20 x 10\(^{-3}\) T. Calculate the radius of the orbit. [Mass of an electron = 9.11 x 10\(^{-3}\) kg; charge on an electron = 1.61 x 10\(^{-19}\)C]

A metallic bar 50 cm long has a uniform cross-sectional area of 4.0 cm\(^2\). If a tensile force of 35 kN produces an extension of 0.25 mm, calculate the value of Young's modulus

(a) Explain how a gas can be made to conduct electricity.

(b) Name the electric charge carriers in gases.

The diagram above represents the graph of electron energy against the frequency of the radiation incident on a metal surface. Interpret the: (a) slope of the graph; (b) intercept, OC; (c) intercept, OK.

(a) State two conditions under which photo-electrons can be emitted from the surface of a metal.

(b) List two particle characteristics of electromagnetic waves.