question_answer 28)

    When an electric field is applied across a semiconductor (a) electrons move from lower energy level to higher energy level in the conduction band (b) electrons move from higher energy level  to lower energy level in the conduction band (c) holes in the valence band move from higher energy level to lower energy level (d) holes in the valence band move from lower energy level to higher energy level

Answer:

  (a,c) When electric field is applied across a  semiconductor, the electrons in the conduction band get accelerated and acquired energy. They move from lower energy level to higher energy level. While the holes in valence band move from higher energy level to lower energy level, where they will be having more energy.