# hnc electrical question

Discussion in 'Homework Help' started by redshaw, Jul 15, 2008.

1. ### redshaw Thread Starter Member

Jul 15, 2008
12
0
hi guys

sorry to trouble you

i am a novice when it comes to electrics but i must complete an electrics assignment for my hnc

i was wondering if you could help me with this question which should get me well on my way.

a resistor of 250 ohms is connected in series with a 1.5 H inductor, accross a 100 V, 50 Hz supply. Calculate a.) current flowing b.) the curcuit phase angel, c.) the p.d voltage across each component and d.) the power dissipated.

any help would be greatly appreciated

cheers

2. ### Ratch New Member

Mar 20, 2007
1,068
3
redshaw,

Yes, that is the first thing to do when analyzing series circuits. By the way, current does not flow, it exists. It is charge that flows. First find the impedance. Begin by calculating the reactance of the inductor. Then add the resistance and the reactance vectorially to get the impedance. You know that reactance is 90 degrees out of phase with the resistance, don't you? Then use the impedance formula and divide the impedance into the voltage to get the current. Multiplying the current by the resistance gives the voltage across the resistor. Ditto for the inductance. I^2*R gives the power dissipated by the resistor. No power is dissipated by the inductance. I did not give you a detailed solution because you should know how to do the steps and have a idea of how things relate to each other. Ratch