Class 12 Physics Semiconductor Electronics PDF

Class 12 Physics Semiconductor Electronics: Materials, Devices and Simple Circuits Daily Practice Problems – II 1. The PN junction diode is used as (...

Class 12 Physics Semiconductor Electronics: Materials, Devices and Simple Circuits Daily Practice Problems – II 1. The PN junction diode is used as (a) An amplifier (b) A rectifier (c) An oscillator (d) A modulator 2. In a PN-junction diode not connected to any circuit (a) The potential is the same everywhere (b) The P-type is a higher potential than the N-type side (c) T  here is an electric field at the junction directed from the N- type side to the P- type side (d) T  here is an electric field at the junction directed from the P-type side to the N-type side 3. The maximum efficiency of full wave rectifier is (a) 100% (b) 25.20% (c) 40.2% (d) 81.2% 4. The diode shown in the circuit is a silicon diode. The potential difference be- tween the points A and B will be (a) 6 V (b) 0.6 V (c) 0.7 V (d) 0 V 5. Which one of the following statements is not correct (a) A diode does not obey Ohm’s law (b) A  PN junction diode symbol shows an arrow identifying the direction of current (forward) flow (c) An ideal diode is an open switch (d) An ideal diode is an ideal one way conductor 1 Class 12 Physics 6. The current through an ideal PN-junction shown in the following circuit dia- gram will be (a) Zero (b) 1 mA (c) 10 mA (d) 30 mA 7. If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be (a) 50 Hz (b) 70.7 Hz (c) 100 Hz (d) 25 Hz 8. In a full wave rectifiers, input ac current has a frequency ‘v’. The output fre- quency of current is (a) v/2 (b) v (c) 2v (d) None of these 9. In comparison to a half wave rectifier, the full wave rectifier gives lower (a) Efficiency (b) Average dc (c) Average output voltage (d) None of these 10. Select the correct statement (a) In a full wave rectifier, two diodes work alternately (b) In a full wave rectifier, two diodes work simultaneously (c) The efficiency of full wave and half wave rectifiers is same (d) The full wave rectifier is bi-directional. 2