Very Short Question and Answers - Electric Current and Circuit

Electric current is the flow of electric charge through a conductor.

Electrons are mainly responsible for carrying current in metals.

The formula is I = Q/t, where I is the current, Q is the charge, and t is the time.

The SI unit of electric current is the ampere (A).

Q = I × t = 2 A × 5 s = 10 C. So, 10 coulombs of charge flows.

Conventional current flows from the positive terminal to the negative terminal of the source, outside the cell.

Electrons flow from the negative terminal to the positive terminal, which is opposite to the direction of conventional current.

An electric circuit is a closed continuous conducting path in which electric current can flow.

Current does not flow in an open circuit because the path is broken.

Two basic components are: (1) a cell or battery and (2) connecting wires.

A switch opens or closes a circuit, allowing or stopping the flow of current.

If the wire is removed, the circuit becomes open and the bulb will not glow.

A torch uses a closed circuit to light up the bulb.

Circuit diagrams save time, are easier to understand, and use standard symbols for clarity.

A cell is represented by two parallel lines; the longer line is positive, and the shorter line is negative.

A resistor restricts or limits the flow of electric current in a circuit.

An ammeter measures electric current (connected in series), and a voltmeter measures potential difference or voltage (connected in parallel).

A closed switch symbol indicates that the circuit is complete and current can flow.

No, because an open circuit does not allow current to flow through the bulb.

Examples: (1) Electric bell—pressing the button completes the circuit; (2) Room lights—switching on completes the circuit and lights up the bulbs.