The output of a linear time invariant control system is $$c(t)$$ for a certain input $$r(t).$$ If $$r(t)$$ is modified by passing it through a block whose transfer function is $${e^{ - s}}$$ and then applied to the system, the modified output of the system would be

The number of roots on the equation $$2{s^4} + {s^3} + 3{s^2} + 5s + 7 = 0$$ that lie in the right half of $$S$$ plane is:

The open collector outputs of two$$2$$-inputs $$NAND$$ gates are connected to a common pull up resistor. If the input to the gates are $$P,Q$$ and $$R,S$$ respectively, the output is equal to

Match the following