1. A 50 W light bulb has a current of 2.5 A flowing through it. Calculate (a) the number of electrons

passing through a cross-section of the filament (b) the number of electrons that pass the cross- section between 1 hours and 30 minutes.

2. How much current is flowing in a circuit where 1.27 1015 electrons move past a given point in 100 ms?

3. The potential difference across a battery is 11 V. How much charge must it deliver to do 29.5 J of work?

4. How much work will be done by an electric energy source with a potential difference of 3 kV that delivers a current of 1 A for 1 minute and 45 seconds?