Question 1

What is an ampere?

Accepted Answer

An ampere (A) is the SI base unit of electric current. It is defined by fixing the elementary charge e = 1.602176634 × 10⁻¹⁹ C.

Question 2

What electric currents are dangerous to humans?

Accepted Answer

Currents above 30 mA through the body can cause cardiac arrest. A 0.2 A current is potentially lethal. By comparison, a smartphone charger delivers about 1–2 A, and a household circuit breaker trips at 15–20 A.

Question 3

What are abampere and statampere used for?

Accepted Answer

The abampere (1 abA = 10 A) belongs to the CGS-EMU system used in theoretical physics. The statampere (1 statA ≈ 3.336 × 10⁻¹⁰ A) belongs to the CGS-ESU system. Both appear in older electromagnetic literature.

Question 4

What is the difference between AC and DC current?

Accepted Answer

DC (direct current) flows in one direction at a constant value, as in batteries. AC (alternating current) reverses direction periodically, typically at 50 or 60 Hz, as in household outlets.

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