Question 1 |

The transfer function of a real system, H(s), is given as:

H(s)=\frac{As+B}{s^2+Cs+D}

where A, B, C and D are positive constants. This system cannot operate as

H(s)=\frac{As+B}{s^2+Cs+D}

where A, B, C and D are positive constants. This system cannot operate as

low pass filter. | |

high pass filter | |

band pass filter. | |

an integrator. |

Question 1 Explanation:

Put s=0, H(0)=\frac{A \times 0+B}{0+C \times 0+D}=\frac{B}{D}

So, the system pass low frequency component. Put s=\infty , H(\infty )=0

For high pass filter, high frequency component should be non zero. Hence this system cannot be operated as high pass filter.

So, the system pass low frequency component. Put s=\infty , H(\infty )=0

For high pass filter, high frequency component should be non zero. Hence this system cannot be operated as high pass filter.

Question 2 |

An air-core radio-frequency transformer as shown has a primary winding and a secondary winding. The mutual inductance M between the windings of the transformer is ____________ \mu H.(Round off to 2 decimal places.)

12.14 | |

68.26 | |

51.1 | |

78.4 |

Question 2 Explanation:

\begin{aligned} I_{1}&=\frac{5}{22}(p-p) \\ V_{0}&=j \omega M I_{1}=7.3=\left(2 \pi \times 10 \times 10^{3}\right) \times M \times\left(\frac{5}{22}\right) \\ M&=51.10 \mu \mathrm{H} \end{aligned}

Question 3 |

The input impedance, Z_{in}\left ( s \right ) for the network shown is

\frac{23s^{2}+46s+20}{4s+5} | |

6s+4 | |

7s+4 | |

\frac{25s^{2}+46s+20}{4s+5} |

Question 3 Explanation:

Circuit in s-domain,

\begin{aligned} -S I_{1}+(4 s+5) I_{2} &=0 \\ \Rightarrow\qquad \qquad I_{2} &=\frac{s}{4 s+5} I_{1} \\ V_{1} &=(4+6 s) I_{1}-\frac{s^{2}}{4 s+5} I_{1} \\ \frac{V_{1}}{I_{1}} &=\frac{(4+6 s)(4 s+5)-s^{2}}{4 s+5} \\ &=\frac{24 s^{2}+30 s+16 s+20-s^{2}}{4 s+5} \\ Z_{\text {in }} &=\frac{23 s^{2}+46 s+20}{4 s+5} \end{aligned}

\begin{aligned} -S I_{1}+(4 s+5) I_{2} &=0 \\ \Rightarrow\qquad \qquad I_{2} &=\frac{s}{4 s+5} I_{1} \\ V_{1} &=(4+6 s) I_{1}-\frac{s^{2}}{4 s+5} I_{1} \\ \frac{V_{1}}{I_{1}} &=\frac{(4+6 s)(4 s+5)-s^{2}}{4 s+5} \\ &=\frac{24 s^{2}+30 s+16 s+20-s^{2}}{4 s+5} \\ Z_{\text {in }} &=\frac{23 s^{2}+46 s+20}{4 s+5} \end{aligned}

Question 4 |

The line currents of a three-phase four wire system are square waves with amplitude of 100 A. These three currents are phase shifted by 120^{\circ} with respect to each other. The rms value of neutral current is

0 A | |

\frac{100}{\sqrt{3}} A | |

100 A | |

300 A |

Question 4 Explanation:

I_N=I_a+I_b+I_c

(I_N)_{rms}=100A

Question 5 |

The graph of a network has 8 nodes and 5 independent loops. The number of branches of
the graph is

11 | |

12 | |

13 | |

14 |

Question 5 Explanation:

Loops =b-(N-1)

5=b-(8-1)

b=12

5=b-(8-1)

b=12

There are 5 questions to complete.