1. EXAMPLE 27.1: A copper wire carries a current of 10 A. It has a cross- sectional area of 0.05 cm 2. Estimate the drift velocity of the electrons.

2. EXAMPLE 27.2: The radius of #8 copper wire is 1.63 mm. A potential difference of 60 V is applied across a 20-m length of this wire. Find: (a) its resistance; (b) the current; (c) the electric field.

3. Find the resistance if currents flow from (a) B to A, (b) C to D

4. EXAMPLE 27.3: The heating element of a space heater is rated at 1000 W when operating at 120 V. (a) What is the current through it under normal conditions? (b) What would its power consumption be if the potential difference drops to 110 V?

5. DISCUSSIONS RQ- ohm’s law

6. Exercises of chapter 27 Questions:7,8,13 Exercises:3,8,13,34,42 Problem:2,4,6,