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Electric Current

Electric current is the rate at which electric charge flows through a conductor.

In one line: Current means charge flow per second.

Practice This Concept

Understand it

In simple terms, current tells us how fast charge is moving in a circuit. If more charge passes a point in less time, the current is larger. Its SI unit is ampere, and it is a basic quantity used in every circuit calculation.

Example

If 10 coulombs of charge pass through a wire in 2 seconds, the current is 5 ampere.

Formula and rule

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

1 A = 1 C/s.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

A wire carries 12 C of charge in 3 s.

  1. 1Using I = Q/t, current = 12/3 = 4 A.
  2. 2So the current in the wire is 4 ampere.

Method you can reuse

  1. 1Note the charge Q in coulombs.
  2. 2Note the time t in seconds.
  3. 3Apply I = Q/t.
  4. 4Divide carefully and write the answer with unit A.

Sketch it in your answer

Draw a simple circuit with a battery, a wire, and an ammeter connected in series. Mark the direction of conventional current clearly.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

If 15 C of charge passes through a wire in 5 s, what is the current?

Think first, then show answer
The current is 3 A because current equals charge divided by time, so 15 divided by 5 gives 3 ampere.

Common wrong answer

A common wrong answer is to write 12 A for 12 C in 3 s.

Why it loses marks: Current is a rate, not the total charge.

Don't mix this up

Many students write the total charge as current instead of dividing charge by time.

Exam tip

Always write the unit as ampere and use I = Q/t in numerical questions.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

Usually asked as a short numerical using charge and time, or as a concept question on the meaning of ampere.
  1. 1

    Enough for 1 mark

    Electric current is the rate at which electric charge flows through a conductor.

  2. 2

    Add for 2 marks

    Example: If 10 coulombs of charge pass through a wire in 2 seconds, the current is 5 ampere.

  3. 3

    Add for 3 marks

    In simple terms, current tells us how fast charge is moving in a circuit.

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