1. Which of the following device has characteristic close to that of an ideal voltage source?
A. Zener diode
B. Vacuum diode
C. Crystal diode
D. All of the above

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2. Which of the following device has characteristics closed to that of an ideal current source?
A. Gas diode
B. Crystal diode
C. Transistor is CB mode
D. All of the above

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3. Which of the following material finds application in light emitting diodes?
A. Silicon
B. Phosphorous
C. Sulphur
D. Gallium phosphide

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4. Which of the following material is used for infra-red LED's?
A. Gallium arsenide
B. Galcium phosphide
C. Silicon
D. None of the above

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5. A Zener diode
A. has a high forward-voltage rating
B. has a sharp breakdown at low reverse voltage
C. is useful as an amplifier
D. has a negative resistance

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6. LEDs normally work on a voltage of
A. Ito 2 V
B. 10 to 20 V
C. 50 to 60 V
D. 100 to 250 V

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7. The power consumption of LEDs may be of the order of
A. 5 to 10 nano amperes
B. 5 to 10 micro amperes
C. 5 to 10 milliamperes
D. 5 to 10 amperes

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