*4. a) Characterize the following systems as being either linear or nonlinear, either time invariant or time varying, and causal or noncausal: (a) y(n) = (n + 3)x(n – 4), (b) y(n) = x²(n+ 1). b) Establish whether the following systems are stable/unstable: i) y(n) = 2 + x²(n) n-1 ii) y(n) = E[2x(k) + 3x(k-1)] k=-00

Q3/ In the system shown in below figure, the numerical values of m, b, and k are given as m = 1 kg,b = 0.3 N – sec/m, and k = 1 N/m, if the system is forced by P = u(t) , find the value of the second pick of x(t) ? m

Find the numerical value of the capacitance per unit length of two long parallel wires (both parallel to the x axis in the xy plane), each with radius 1 mm, with their centers separated by 4 mm. Express your answer in picofarads per meter. You may assume the wires are perfect conductors.

• Eleven Thyristor used in a string withstanding voltage is 5kV, the maximum leakage current and recovery charge difference are 1mA and 2µC respectively, the capacitor and across resistor are 0.1µF and 10kn, respectively. Calculate transient and steady-state derating factor?