(a) The temperature coefficient of resistivity of copper is 3.9 x 103K. The resistivity of copper1 mm is heated to 80°C.1.72 x 10-8 m at 20°C. A copper wire of

length 10 cm and diameter i. Calculate the resistivity of copper at 80°C. ii. The wire is connected to a battery providing a voltage of 1.5 V. Calculate the power dissipated in the wire. A sphere of radius R carries a charge density \rho(r)=\frac{5 Q r^{2}}{4 \pi R^{5}} where r is the radial distance from the centre of the sphere. i. Sketch the charge densityas a function of r from r = 0 to r = 2R. ii. Show that the total charge of the sphere is Q. iii. Calculate the electric field E inside the sphere. iv. Calculate the electric field outside the sphere. v. Sketch the electric field magnitude as a function of r from r = 0 to r = 2R.