TOPIC 5 ELECTRICITY CHAPTER 23 EXERCISE 23A CONTINUED
5. If 15 × 1020 electrons pass a point in a circuit every 10 seconds, what current is fl owing in the circuit?
6. How many electrons are required to pass a point in a circuit to give a charge of 5 C?
7. Calculate the energy produced if 7 A fl ows through a 20 Ω resistor for 10 seconds.
8. Calculate the energy produced if a 13 A current fl ows through a 150 Ω resistor for 30 seconds.
9. An electron gun fi res a beam of electrons at a TV screen. If the beam current is 40 μA, how many electrons strike the screen if the TV is being used for an average of 4 hours a day over a fortnight?
10. If a 4.5 kW appliance requires a current of 5 A, calculate the resistance of the appliance.
11. Calculate the power of a 50 Ω fan with a current of 13 A. If it is left on for 5 hours, what energy is produced?
12. A 50 mA current produces 1 kJ of energy in 2 minutes. What is the resistance in the circuit?
13. Calculate the value of the current on each
ammeter in the circuit shown, if A2 reads 3 A and A4 reads 0.5 A.
