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Browse complete papersFind the voltage regulation of transformer at full load having reactance of 5% and resistance of 2% with a lagging power factor of 0.8.
0.46%
0.38%
3.8%
4.6%
Correct answer
0.46%
A 2000/400V, 10KVA transformer having ohmic loss of 1% and reactance drop of 9%. Find its regulation at unity power factor.
0
1
3.8
2.2
Correct answer
0
In the circuit shown, a 120VDC source is connected to a resistive network. A 12Ω resistor is connected in series with the source and leads to a junction. Calculate the terminal voltage \( V_{AB} \).
From this junction:
· A 20Ω resistor is connected to terminal A
· A 15Ω resistor is connected vertically to terminal B
Assume all resistors are ideal.
65.23
66.12V
66.67
66.15
Correct answer
65.23
Three resistors of 8Ω each are connected in parallel. What is the equivalent resistance?
2.67Ω
3.01Ω
3Ω
1.01Ω
Correct answer
2.67Ω
What is the power consumed by a 40Ω resistor connected directly to a 12V battery?
3.6V
3.6W
2.6W
2.5V
Correct answer
3.6V
A phasor voltage \( V = 100\angle 30^{\circ} \text{ V} \) is applied across an impedance \( Z = 20\angle 35^{\circ} \text{ }\Omega \). Obtain an expression for the instantaneous power and then find the value of the average power fed to the impedance.
Given: \( \omega = 100 \text{ rad} \)
450W
470W
410W
515W
Correct answer
450W
A charge of 12 nC is enclosed inside a closed surface. Calculate the electric flux through this surface (\( \varepsilon_0 = 8.854 \times 10^{-12} F/m \)).
\( 9 \times 10^2 Nm^2/C \)
\( 452 Nm^2/C \)
\( 904 Nm^2/C \)
\( 1.356 \times 10^3 N \)
Correct answer
\( 9 \times 10^2 Nm^2/C \)
What is the speed of propagation for an electromagnetic wave in free space?
\( 3 \times 10^7 m/s \)
\( 1.5 \times 10^8 m/s \)
\( 3 \times 10^8 m/s \)
\( 9 \times 10^8 m/s \)
Correct answer
\( 3 \times 10^7 m/s \)
A lossless transmission line is 1 m long and operates at 500 MHz. Find its characteristic impedance. The line parameters are:
· L = \( 0.4 \mu H/m \)
· C = \( 80 pF/m \)
\( 67.01 \Omega \)
\( 70.7 \Omega \)
\( 80 \Omega \)
\( 105 \Omega \)
Correct answer
\( 67.01 \Omega \)
Two transmission lines connected end-to-end: Line 1 (40 m, 0.08 dB/m attenuation), Line 2 (25 m, 0.2 dB/m attenuation), with a 2 dB joint loss. What percentage of input power reaches the output?
9.5%
8.7%
10.2%
12.5%
Correct answer
9.5%