Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET 202624 AprilMorning Shift
Exam
MHT CET
Year
2026
Date
24 April
Shift
Morning Shift
Subject
Physics
Chapter
Semiconductors

MHT CET 2026 · 24 April · Morning Shift · Physics · Semiconductors

For a common emitter amplifier, the audio signal voltage across the...

For a common emitter amplifier, the audio signal voltage across the collector resistance of 2 kΩ2\ \text{k}\Omega is 4 V. If the current amplification factor of the transistor is 100 and the base resistance is 1 kΩ1\ \text{k}\Omega, then the input voltage is

Options

  1. A10 mV10\ \text{mV}
  2. B15 mV15\ \text{mV}
  3. C20 mV20\ \text{mV}
  4. D25 mV25\ \text{mV}

Correct answer

C. 20 mV20\ \text{mV}

Step-by-step solution

Output voltage Vo=4 VV_o = 4\ \text{V}

Collector resistance Rc=2 kΩ=2000 ΩR_c = 2\ \text{k}\Omega = 2000\ \Omega

Collector current Ic=VoRc=42000=2×10−3 AI_c = \dfrac{V_o}{R_c} = \dfrac{4}{2000} = 2 \times 10^{-3}\ \text{A}

Current amplification factor β=100\beta = 100

Base current Ib=Icβ=2×10−3100=2×10−5 AI_b = \dfrac{I_c}{\beta} = \dfrac{2 \times 10^{-3}}{100} = 2 \times 10^{-5}\ \text{A}

Base resistance Rb=1 kΩ=1000 ΩR_b = 1\ \text{k}\Omega = 1000\ \Omega

Input voltage Vi=IbRb=(2×10−5)×1000=2×10−2 V=20 mVV_i = I_b R_b = (2 \times 10^{-5}) \times 1000 = 2 \times 10^{-2}\ \text{V} = 20\ \text{mV}

Answer: 20 mV20\ \text{mV}
Practice Semiconductors on Quantrex Academy →

More from Semiconductors

For two inputs A and B and output Y, the Boolean expression for NOR gate is MHT CET Medical 2026For an n-type semiconductor, the relation between the number density ' n_h ' and ' n_e '… MHT CET Medical 2026A silicon crystal is doped with 5 × 10^ 17 \ cm^ -3 atoms of boron. The electron… MHT CET Medical 2026If the current gain in common-base configuration (α ) of a transistor increases from 0.95… MHT CET Medical 2026Out of the following what is used to detect the intensity of light ? MHT CET Medical 2026The color of light emitted by an LED is determined primarily by which of the following… MHT CET Medical 2026Which of the following is true for a p-type semiconductor? MHT CET Medical 2026In case of semiconductors, the band gap between the valence band and conduction band is MHT CET Medical 2026 Full Semiconductors list All MHT CET Medical PYQs