In a CE transistor amplifier, the audio signal voltage across the collector resistance of 2kΩ is 2V. If the base resistance is 1kΩ and the current amplification of the transistor is 100, the input signal voltage is

10 mV

The out voltage, across the load $R_C$

$V_0 = I_CR_C = 2$

The collector current $(I_C)$

$I_C=\frac{2}{2×10^3}=10^3Amp$

Current gain (β)

(β) current gain = $\frac{I_C}{I_B}=100$

$I_B=\frac{I_C}{100}=\frac{10^{-3}}{100}=10^{-5}Amp$

Input voltage $(V_i)$

$V_i=R_BI_B=1×10^3×10^{-5}=10^{-2}Volt$

$V_i =10mV$