In the radiation pattern of a 3-element array of isotropic radiators equally spaced at distances of $${\lambda /4}$$ it is required to place a null at an angle of 33.56 degrees off the end-fire direction. Calculate the progressive phase shifts to be applied to the elements. Also calculate the angle at which the main beam is placed for this phase distribution.

A silicon sample is uniformly doped with 10¹⁶ phosphorous atoms/cm³ and 2 ×10¹⁶ boron atoms/cm³. If all the dopants are fully ionized, the material is

The small signal capacitances of an abrupt P⁺−N junction is 1 nF at zero bias. If the built-in voltage is 1 volt, the capacitance at a reverse bias voltage of 99 volts is equal to

Referring to the figure. The switch S is in position 1 initially and steady state conditions exist from time t = 0 to t = t₀. At t = t₀, the switch is suddenly thrown into position 2. The current I through the 10K resistor as a function of time t, from t = 0 is (in mA) _____________.

(Give the sketch showing the magnitudes of the current at t = 0, t = t₀ and t = $$\infty$$ )