Study Guides/Physics/1 Ampere Definition
Study Guide · Physics

1 Ampere Definition – SI Unit of Electric Current

Ampere (A) is the SI unit of electric current. It is named after the French physicist André-Marie Ampère.

Question (Click to Flip)

What is the definition of 1 Ampere?

Answer

1 Ampere is the electric current when 1 Coulomb of charge flows through a conductor in 1 second.

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Key Facts

SI Unit: Ampere (A).

Formula: I = Q/t (1 A = 1 C/s).

1 Coulomb = charge of 6.242 × 10¹⁸ electrons.

Named After: André-Marie Ampère.

Definition of 1 Ampere

Definition 1 (Simple): 1 Ampere is the amount of electric current that flows through a conductor when 1 Coulomb of charge passes through a cross-section of the conductor in 1 second.

Formula: I = Q/t Where: I = Current (Ampere), Q = Charge (Coulomb), t = Time (seconds)

So: 1 A = 1 C / 1 s

New SI Definition (2019)

Since 2019, the Ampere is officially defined as: 'The electric current corresponding to the flow of exactly 6.242 × 10¹⁸ elementary charges (electrons) per second.'

Practical Understanding

  • A mobile phone charger typically uses 1–2 Amperes.
  • A household fan uses about 0.5 Amperes.
  • A lightning bolt carries about 20,000 Amperes (but for a fraction of a second).

Questions and Answers

What is the definition of 1 Ampere?+

1 Ampere is the electric current when 1 Coulomb of charge flows through a conductor in 1 second.

What is the SI unit of electric current?+

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

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