Which of the following units is equivalent to the unit of electric current?

Analyze the question: We need the unit that is equivalent to the ampere (A), the unit of electric current.

Concept: Current is the rate of flow of charge:

I = Q / t

So 1 ampere = 1 coulomb per second, which is 1 C s⁻¹.

Check each option:

• A. C s⁻¹ is charge divided by time, which is exactly the definition of current. ✔
• B. W (watt) is the unit of power, not current. ✘
• C. J s⁻¹ is energy per time, which is also power (1 W = 1 J s⁻¹). ✘
• D. C (coulomb) is the unit of charge. ✘

(The option is written as "C s${-1}$", which is a formatting glitch for C s⁻¹.)

Tip: Think "I = Q/t". Any unit written as coulombs per second is amperes. Also remember that J s⁻¹ and W are the same thing (power), so if two options are equivalent to each other, as B and C are here, neither can be the answer to a single-answer question about current.