# Help with electrical engineering problems watch

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1. Can anyone help with these problems? I just can't do them,if you can explain one of them, I'd be really grateful

1.A choke with an inductance of 20 mH and a series resistance of 5 Ohms is connected in parallel with an ideal capacitor of 3 microFarad. The network is connected to an ideal current source producing signal in a form i(t) = 30cos(3000*t) [mA], where time t is measured in seconds. Determine the apparent power provided by the source.

A 100 mH inductor with equivalent series resistance (resistance IN SERIES with an ideal inductor) of 2 Ohm is connected in parallel with a 10 microFarad capacitor to an ideal voltage source which provides signal in a form v(t) = 165 cos(500*t) [V], where t = time in seconds.
Calculate active power dissipated in inductor due to finite resistance. Assume that the capacitor is ideal.

A voltage v(t) = 35 *cos(wt) [V] at a frequency of 50 Hz is applied to AC motor. The current has peak value of 200 [mA] and it lags behind voltage by 20 degrees.
Calculate the value of instantaneous power delivered by the source to the load at time t1 = 5 microseconds.

An inductive load of 50 kW has the power factor p.f. = 0.7. The power supply is 220 V (rms) at 50 Hz. Find the value of the capacitance in parallel with the load needed to increase the power factor to 0.95.

Two loads are connected in parallel. Load A is 10 kW at pf = 0.8, lagging. Load B has the pf of 0.95, lagging. Find the active power on load B if the total reactive power supplied by the source is Q = 15 kvar.

TRANSMISSION LINE. The distributed parameters of a transmission line are as follows: C' = 50 pF/m; L' = 0.12 microHenry/m ; R'=8e-4 Ohm/m; G' =2e-4 Siemens. Find characteristic impedance at frequency f = 100 kHz.

TRANSMISSION LINE. A load is connected to a lossless transmission line with impedance of 50 Ohms. The load impedance is (33 - 22j) Ohms.
Find the power absorbed by the load if the input power is 100 W.

TRANSMISSION LINE. Find the input impedance of a 30 Ohm transmission line terminated with an open circuit. The length of the line is 2.15*lambda, where lambda is the signal wavelength. The loss in the line is negligible.
2. I recommend you draw circuit diagrams for most of these to see what's going on.

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Updated: December 1, 2014
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