three resistance of 3,4 and 12 ohms are connected and parallel and a voltage of of 6 volts applied to the __?

Question

combination (1) find the current thru the combination (2) the current thru each branch..

Answer 1

Resistance for the combination = 1/ (1/3+1/4 + 1/12) = 12/(4+3+1) = 12/8 = 1.5 ohms

Current through combination = 6V/1.5 ohms = 4 A.
Current through 3 Ohm = 6V/2 Ohm = 2A
Current through 4 Ohm = 6V/4 Ohm = 1.5A
Current through 12 Ohm = 6V/12 Ohm = 0.5A

Answer 2

(1)
the Rc= (3^-1 + 4 ^-1 + 12^-1)^-1 = 3/2 (ohms)
the current thru the combination:
I = U/Rc= 6/ (3/2) = 4 (A)

(2)
The current thru each branch:
(Let I1 be the current thru the resistance of 3
I2 be the current thru the resistance of 4
I3 be the current thru the resistance of 12)
I1= U/R1= 6/3=2
I2=U/R2=6/4= 3/2
I3=U/R3=6/12=1/2

Answer 3

You can do it two ways to find total resistance first.
You can use the product over sum method.

3 * 4 * 12
------------- = 1.5 ohms
3+ 4+ 12

or you can use the reciprocal method.

.. . . 1
---------------------- = 1.5 ohms:
1/3 + 1/4 + 1/12

Current through the combination means total current.

To get that use ohms law and simply divide the applied voltage by the total resistance.
Ohms law revisited:

..E
---------
I * R
trick once you have it set up like that is simply put your finger which one you what to find in this case total current flow:

Let @ be my finger.
...E
------ = I
@ R

I = 6/1.5
I = 4 amps total current flowing in the circuit.

Next use ohms law to get the current through each branch.

6 / 3 = 2 amps flowing through 3 ohm resistor
6 / 4 = 1.5 amps flowing through the 4 ohm resistor
6 / 12 = 0.5 amps flowing through the 12 ohm resistor

You can find the currents flowing through each branch the add them together to find total current also. with out having to find total resistance of the circuit.

If you add the currents flowing through each branch it also comes out ot 4 amps

Another way to find total reistance is one you have the total current use ohms law again to find total resistance.

E / I = R
6 volts / 4 amps = 1.5 ohms resistance.

Answer 4

1) 4 amps
2) 2, 1,5, 0,5 amps