Quantization of Electric Charge

Steps:

• Current I is the rate of charge flow: I = ΔQ / Δt for small intervals.
• Total charge Q through the resistor is Q = I × Δt, the integral of current over time.
• Electric charge is quantized; it consists of discrete electrons or ions, each carrying charge ±e (elementary charge).
• Thus, Q equals N × e, where N is the integer number of charge carriers passing through.

Why B is correct:

• Charge quantization principle states that all free charges in matter are integer multiples of e ≈ 1.6 × 10⁻¹⁹ C, so total charge passed must be N × e.

Why the others are wrong:

• A: Quantization restricts Q to discrete multiples of e, not arbitrary values.
• C: Q equals one e only if exactly one charge carrier passes, which is unlikely for any current.
• D: Current I is the rate of charge flow (Q/t), not the total charge Q itself.

Final answer: B