List of practice Questions

In the circuit shown, the identical transistors Q1 and Q2 are biased in the active region with \( \beta = 120 \). The Zener diode is in the breakdown region with \( V_Z = 5 \, V \) and \( I_Z = 25 \, mA \). If \( I_L = 12 \, mA \) and \( V_{EB1} = V_{EB2} = 0.7 \, V \), then the values of \( R_1 \) and \( R_2 \) (in \( k\Omega \), rounded off to one decimal place) are _________, respectively.


 

The electron mobility \( \mu_n \) in a non-degenerate germanium semiconductor at 300 K is 0.38 m$^2$/Vs. The electron diffusivity \( D_n \) at 300 K (in cm$^2$/s, rounded off to the nearest integer) is _________.
A square metal sheet of 4 m \( \times \) 4 m is placed on the x-y plane as shown in the figure below. If the surface charge density (in \( \mu \)C/m\(^2\)) on the sheet is \( \rho_s(x, y) = 4|y| \), then the total charge (in \( \mu \)C, rounded off to the nearest integer) on the sheet is _________.