In circuit notation, which letter is commonly used to denote current?

• A. I
• B. R
• C. V
• D. E

Answer: (A)

Current is represented by the letter I in circuit notation. This convention comes from the word “intensity” (often used to describe the strength of the flow of charge) and is used consistently across circuit theory and textbooks. In Ohm’s law, V = I R, the current I is the quantity that flows through a resistor R, linking it directly to the voltage across the element. The other symbols correspond to different quantities: resistance is denoted by R, voltage or potential difference by V, and E is typically used for electromotive force or energy, not current. So I is the natural and widely accepted symbol for current.