In the system whose signal flow graph is shown in the figure, U_{1}(s) and U2(s) are inputs. The
transfer function Y(s)/U1(s) is

**A. **

**B. **

**C. **

**D. **

**Answer : ****Option A**

**Explaination / Solution: **

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A source is supplying a load through a 2-phase, 3-wire transmission system as shown in figure
below. The instantaneous voltage and current in phase-a are V_{an} = 220sin(100πt)V and i_{a} = 10sin(100πt)A, respectively. Similarly for phase-b the instantaneous voltage and current
are V_{bn} = 220cos(100πt)V and i_{b} = 10cos(100πt)A, respectively.

**A. ** 2200 W

**B. ** 2200sin^{2 }(100πt)W

**C. ** 440 W

**D. ** 2200sin (100πt)cos(100πt)W

**Answer : ****Option A**

**Explaination / Solution: **

The total instantaneous power flowing form the source to the load is

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A 3-bus power system is shown in the figure below, where the diagonal elements of Y-bus
matrix are Y_{11} = -j12pu, Y_{22} = -j15pu and Y_{33} = -j7pu

**A. ** p = -0.2, q = -0.1, r = -0.5

**B. ** p = 0.2, q = 0.1, r = 0.5

**C. ** p = -5, q = -10, r = -2

**D. ** p = 5, q =10, r = 2

**Answer : ****Option B**

**Explaination / Solution: **

The per unit values of the line reactances p, q and r shown in the figure are

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The bus admittance matrix for a power system network is pu

**A. **

**B. **

**C. **

**D. **

**Answer : ****Option C**

**Explaination / Solution: **

There is a transmission line, connected between buses 1 and 3, which is represented by the
circuit shown in figure.

If this transmission line is removed from service, What is the modified bus admittance matrix?

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A 4 pole induction machine is working as an induction generator. The generator supply frequency is 60 Hz. The rotor current frequency is 5 Hz. The mechanical speed of the rotor in RPM is

**A. ** 1350

**B. ** 1650

**C. ** 1950

**D. ** 2250

**Answer : ****Option C**

**Explaination / Solution: **

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Let z(t) = x(t) * y(t), where "*" denotes convolution. Let C be a positive real-valued constant. Choose the correct expression for z (ct).
**A. ** c.x(ct) * y(ct)

**B. ** x(ct) * Y(ct)

**C. ** c.x(t) * y(ct)

**D. ** c.x(ct) * y(t)

**Answer : ****Option A**

**Explaination / Solution: **

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Consider the system with following input-output relationwhere, x[n] is the input and y[n] is the output. The system is

**A. ** invertible and time invariant

**B. ** invertible and time varying

**C. ** non-invertible and time invariant

**D. ** non-invertible and time varying

**Answer : ****Option D**

**Explaination / Solution: **

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Let a causal LTI system be characterized by the following differential equation, with initial rest condition

Where x(t) and y(t) are the input and output respectively. The impulse response of the system is (u(t) is the unit step function)

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Let the signal be passed through an LTI system with frequency
response H(𝜔), as given in the figure below

**A. ** 4000 + 4000cos(2000πt) + 4000cos(4000πt)

**B. ** 2000 + 2000cos(2000πt) + 2000cos(4000πt)

**C. ** 4000cos(2000πt)

**D. ** 2000cos(2000πt)

**Answer : ****Option C**

**Explaination / Solution: **

The Fourier series representation of the output is given as

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Consider an electron, a neutron and a proton initially at rest and placed along a straight line such that the neutron is exactly at the center of the line joining the electron and proton. At t=0, the particles are released but are constrained to move along the same straight line. Which of these will collide first?

**A. ** The particles will never collide

**B. ** All will collide together

**C. ** Proton and Neutron

**D. ** Electron and Neutron

**Answer : ****Option D**

**Explaination / Solution: **

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