Help needed on science questions!

[Dannywhite]

im extremely stuck on this mock exam, the real one is tomorrow so I need to pass, however I'm stuck on these 3 questions, they are simple probably but it's the way it's worded that she gets me.

1.) explain the effect resistance has on current in an ac circuit.

2.) explain what's forms the opposition to current change in an ac inductive or capacitive circuit.

3.) explain what forms the total opposition to current flow in an ac circuit containing inductance and resistance.

 

[telectrix]

1.) explain the effect resistance has on current in an ac circuit.

think what happens if (a) you increase resistance: (b) decrease resistance

2.) explain what's forms the opposition to current change in an ac inductive or capacitive circuit.

think impedance. reactance with capacitance, inductance with inductive load.

3.) explain what forms the total opposition to current flow in an ac circuit containing inductance and resistance.

combination of both R and L.

 

[Dannywhite]

Still no idea mate my brain is fried, I'm guessing if you increase resistance the current decreases and the other way around ? If you decrease resistance the current will increase ?

 

[telectrix]

correct. ohms law. I = V/R.

 

[Dannywhite]

So what about the last two questions ?

 

[FatAlan]

What's the exam?

 

[Dannywhite]

The science principles one

 

[telectrix]

both capacitance and inductance provide impedance to current flow. the calc.s are abit more complex. have a read through this:

How we classified resistive , capacitive & inductive loads ? thanks - http://www.edaboard.com/thread229252.html

 

[D00DY_T00DY]

Think of voltage and amps as water flowing through a pipe. So the voltage is the amount of water flowing and amps the pressure of the water. So essentially resistance is the size of the pipe. Lower the size of the pipe(or cable) the harder it is to make it through. Thus increasing the resistance.

Same applies with length of cable. Longer the cable run harder it is for the electrickery to make it to the other end.
Might be a bit easier to get your head around it.

Also now you can become a plumber