Q19. the energy of an electron in a band as a function of its wave vector k is given by ek)= e, - bcos k,a + cosk,a + cos k.a) where e, b and a are constants. t

Q19. The energy of an electron in a band as a function of its wave vector k is given by Ek)= E, - Bcos k,a + cosk,a + cos k.a) where E, B and a are constants. The effective mass of the electron near the bottom of the band is 2h2 (a) 3Ba Ans (d) h (b 3Ba2 (c) 2 Ba2 h (d) Ba