49. In a n-type semiconductor, which of the following statement is true?

48. In an unbiased p − n junction, holes diffuse from the p-region to n-region because of ___ ?

47. Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is :

47. Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is :

46. C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because :

46. C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because :

(a) In case of C the valence band is not completely filled at absolute zero temperature.

(b) In case of C the conduction band is partly filled even at absolute zero temperature.

(c) The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.

(d) The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.

Answer :  (c) The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.

45. In forward biasing of the p − n junction ___ ?

44. If a small amount of antimony is added to germanium crystal ___ ?

43. In the following figure, the diodes which are forward biased, are ?

42. Pure Si at 500 K has equal number of electron (ne) and hole (nh) concentrations of 1.5 × 1016 m−3 . Doping by indium increases nh to 4.5 × 1022 m−3 . The doped semiconductor is of ?

41. A zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in figure. The current through the diode is ?

41. A zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in figure. The current through the diode is ?

40. Which one of the following statement is FALSE ?

39. Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point ?

38. A p−n photodiode is fabricated from a semiconductor with a band gap of 2.5eV. It can detect a signal of wavelength ?

37. Sodium has body centred packing. Distance between two nearest atoms is 3.7Â. The lattice parameter is ?

36. A p-n photodiode is made of a material with a band gap of 2.0eV. The minimum frequency of the radiation that can be absorbed by the material is nearly ?

35. For a cubic crystal structure which one of the following relations indicating the cell characteristics is correct?

34. In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is ?

34. In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is ?

33. Choose the only false statement from the following