Alpha of a bipolar transistor is equal to:

Alpha and beta are the two primary current gain parameters of a bipolar junction transistor. Alpha is the common-base current gain (Ic / Ie), while beta is the common-emitter current gain (Ic / Ib). Because the emitter current is always the sum of the collector and base currents (Ie = Ic + Ib), you can express alpha entirely in terms of beta. By substituting and rearranging the fundamental current equations, you arrive at the standard conversion formula: alpha = beta / (1 + beta). Since beta is typically a large number (e.g., 100), alpha is always slightly less than 1 (e.g., 100 / 101 = 0.99). The other distractors present mathematically incorrect manipulations of this fundamental relationship.