The value of hie in ohms for a BJT with I_C = 3 mA, V_T = 25 mV and h_fe = 150 is: 

Concept

The input resistance of the CE amplifier is given by:

\(h_{ie}={h_{fe}\over g_m}\)

where, h_ie = Input resistance

h_fe = Current gain

g_m = Transconductance

The transconductance is given by:

\(g_m={I_c\over V_T}\)

where, I_c = Collector current

V_T = Thermal voltage

Calculation

Given, Ic = 3 mA, hfe = 150

VT = 25 mV 

\(g_m={3\over 25}\)

\(h_{ie}={150\times 25\over 3}\)

hie = 1250 Ω