Concept:In a transistor symbol, the arrow is drawn on the emitter lead. It shows the direction of conventional current, which is the direction in which positive charges (holes) move.
Solution:Conventional current is taken as the flow of positive charge.
In a semiconductor, the positive charge carriers are called holes, so holes move in the direction of the arrow.
Electrons (negative charges) move in the opposite direction to the arrow, so options A and D are wrong.
The arrow shows one direction only, so it cannot show both electron and hole movement (option C).
Key point: The symbol shown, with the arrow pointing out of the emitter, is an NPN transistor. In every transistor symbol the arrow points from the P region to the N region, the way conventional current (and holes) flow.
Answer:Option B (hole movement)
