NEET Physics is the very imporatant paper in the Medical Entrance EXAM. So these NEET Physics MCQs with Answers for all Concepts as per the new syllabus. Practice daily with these NEET Physics objective questions on air pollution knowledge & problem-solving skills along with time management. NEET Physics Valve Electronics (Diode and Triode) Multiple Choice Questions make you feel confident in answering the question in the
MCQs on Valve Electronics (Diode and Triode) :
1. Number of secondary electrons emitted per number of primary electrons depends on
(A) Material of target
(B) Frequency of primary electrons
(C) Intensity
(D) None of the above
Answer
Answer: (C) Intensity
2. In a diode, when there is saturation current, the plate resistance is
(A) Zero
(B) Infinite
(C) Some finite quantity
(D) Data is insufficient
Answer
Answer: (B) Infinite
3. The grid voltage of any triode valve is changed from 1 volt to 3 volt and the mutual conductance is 3 x 10-4 mho. The change in plate circuit current will be
(A) 0.8 mA
(B) 0.6 mA
(C) 0.4 mA
(D) 1 mA
Answer
Answer: (B) 0.6 mA
4. For a given plate voltage the plate current in a triode is maximum when the potential of
(A) The grid is positive and the plate is negative
(B) The grid is positive and the plate is positive
(C) The grid is zero and the plate is positive
(D) The grid is negative and the plate is positive
Answer
Answer: (B) The grid is positive and the plate is positive
5. The amplification factor of a triode is 20. If the grid potential is reduced by 0.2 volt then to keep the plate current constant its plate voltage is to be increased by
(A) 10 volt
(B) 4 volt
(C) 40 volt
(D) 100 volt
Answer
Answer: (B) 4 volt
6. The amplification produced by a triode is due to the action of
(A) Filament
(B) Cathode
(C) Grid
(D) plate
Answer
Answer: (C) Grid
7. In a triode amplifier, the value of maximum gain is equal to
(A) Half the amplification factor
(B) Amplification factor
(C) Twice the amplification factor
(D) Infinity
Answer
Answer: (B) Amplification factor
8. The voltage gain by the triode depends on
(A) Filament voltage
(B) Plate voltage
(C) Plate resistance
(D) Plate current
Answer
Answer: (C) Plate resistance
9. In a triode valve
(A) If the grid voltage is zero then plate current will be zero
(B) If the temperature of the filament is doubled, then the thermionic current will also be doubled.
(C) If the temperature of the filament is doubled, then the thermionic current will nearly be four times
(D) At a definite grid voltage, the plate current varies with plate voltage according to Ohm’s law
Answer
Answer: (C) If the temperature of the filament is doubled, then the thermionic current will nearly be four times
10. In the circuit of a triode valve, there is no change in the plate current, when the plate potential is increased from 200 volt to 220 volt and the grid potential is decreased from 0.5 volt to 1.3 volt. The amplification factor of the valve is
(A) 15
(B) 20
(C) 25
(D) 35
Answer
Answer: (C) 25