Q. In the given circuit, assume that the opamp is ideal and the transistor has a b of 20. The current Io (in mA) flowing through the load ZL is _      . Ans: 300

Q. An ideal square wave with period of 20 ms shown in the figure, is passed through an ideal low pass filter with cut-off frequency 120 Hz. Which of the following is an accurate description of the output? A. Output is zero. B. Output consists of both 50 Hz and 100 Hz frequency components. C.

Q. Two periodic signals 𝑥(𝑡) and 𝑦(𝑡) have the same fundamental period of 3 seconds. Consider the signal 𝑧(𝑡) = 𝑥(−𝑡) + 𝑦(2𝑡 + 1). The fundamental period of 𝑧(𝑡) in seconds is (A) 1                           (B) 1.5                        (C) 2                          (D) 3 Ans: 3 Sol:

Q. A coil having an impedance of (10 + j100) Ω is connected in parallel to a variable capacitor as shown in figure. Keeping the excitation frequency unchanged, the value of the capacitor is changed so that parallel resonance occurs. The impedance across terminals p-q at resonance (in Ω) is   Ans: 1009 – 1011

Q. The Thevenin equivalent circuit representation across terminals p-q of the circuit shown in the figure is a (A) 1 V source in series with 150 kΩ            (B) 1 V source in parallel with 100 kΩ (C) 2 V source in series with 150 kΩ            (D) 2 V source in parallel with 200 kΩ Ans:

Q. A series R-C circuit is excited by a 1Ð0 V sinusoidal ac voltage source. The locus diagram of the phasor current 𝐼= (x + jy) A, when C is varied, while keeping R fixed, is Ans: Option 1

Q. Consider two functions 𝑓(𝑥) = (𝑥 − 2)2 and 𝑔(𝑥) = 2𝑥 − 1, where 𝑥 is real. The smallest value of 𝑥 for which 𝑓(𝑥) = 𝑔(𝑥) 𝑖𝑠 __________. Ans: 1

Q. 𝑋 and 𝑌 are two independent random variables with variances 1 and 2, respectively. Let 𝑍 = 𝑋 − 𝑌. The variance of 𝑍 is (A) 0                           (B) 1                           (C) 2                          (D) 3 Ans: 3

Q. Let  𝑓1(𝑧) = 𝑧2    and  𝑓2(𝑧) = 𝑧̅ be two complex variable functions. Here 𝑧̅   is the complex conjugate of z. Choose the correct answer. A. Both 𝑓1(𝑧) and 𝑓2(𝑧) are analytic B. Only 𝑓1(𝑧) is analytic C. Only 𝑓2(𝑧) is analytic D. Both 𝑓1(𝑧) and 𝑓2(𝑧) are not analytic Ans: Only 𝑓1(𝑧) is

Q. Let 𝑁 be a 3 by 3 matrix with real number entries. The matrix 𝑁 is such that 𝑁2 = 0. The eigen values of N are (A) 0, 0, 0                   (B) 0,0,1                     (C) 0,1,1                    (D) 1,1,1 Ans: 0, 0, 0