Define electric current. What is the SI unit of electric current.

The p.d. across a lamp is 12 V. How many joules of electrical energy are changed into heat and light when:

(a) a charge of 1 C passes through it?

(b) a charge of 5 C passes through it?

(c) a current of 2 A flows through it for 10 s?

In 10 s, a charge of 25 C leaves a battery, and 200 J of energy are delivered to an outside circuit as a result.

(a) What is the p.d. across the battery?

(b) What current flows from the battery?

One coulomb of charge flows through any cross-section of a conductor in 1 second. What is the current flowing through the conductor?

Which instrument is used to measure electric current? How should it be connected in a circuit?