Circuits

[bluemoon]

An Electric DC Circuit is attached to a 12-volt batter and has a 3-ohm resistor in it.

Find the current flowing through the circuit

What is the current in an AC Circuit with 120 volts and a 60 watt light bulb?

I wasn't very good at circuits at all. Help please?

[Turtle]

Originally Posted by bluemoon

An Electric DC Circuit is attached to a 12-volt batter and has a 3-ohm resistor in it.

Find the current flowing through the circuit

What is the current in an AC Circuit with 120 volts and a 60 watt light bulb?

I wasn't very good at circuits at all. Help please?

What you need is Ohms Law & some elbow grease.
http://jersey.uoregon.edu/vlab/Voltage/

[ronthepon]

I understand your problem, bluemoon, we are very close by on the academic ladder. I'm telling you all this because even I wanna revise

Ohm's law is like:
V=IR

V is the potential difference across the resistor
I is the current flowing through th resistor
R is the resistance.

So lets solve your first question

An Electric DC Circuit is attached to a 12-volt batter and has a 3-ohm resistor in it.Find the current flowing through the circuit

V= 12 Volts
R= 3 Ohms

So 12=(I)3

giving I= 4 Amperes

Now your second one

What is the current in an AC Circuit with 120 volts and a 60 watt light bulb?

Remember that the bulb is using 60 watts when you supply 120 volts.
So
its using 60 Joules used per second.

Use the equations: P=(V^2)/R(means V squared divided by R) and P=(I^2)R
The symbols have the usual significance.

So, P=60 Joules per second
V= 120 Volts

We get 60=120*120/R
Solving, R=240 Ohms

Now we can use this in the second equation I mentioned.

60=(I^2)240

I^2=1/4

I=1/2 = 0.5 Amperes

Thats all! So simple for theory.

Want a tip to excel in your exams?
Won't you bother to read your textbooks to get the concepts? No hope for you if you don't...