In a complete circuit the resistance of the first device is 12 ohms the resistance of the second device is 4 ohms and the voltage developed by the generator is 40 v what is the magnitude of the curren?

Answer 1

If the devices are in series, then the current from the generator is (40/16) = 2.5 Amp.

If the devices are in parallel, then the current from the generator is (40/3) = (13 and 1/3) Amp.

Answer 2

That would depend on the type of connection. If all the elements are connected in series, then you could use Ohm's Law (V = IR) I = V/R = 40/16 A. If they are connected in parallel, it would be I = V/R = 40/12 A whats the answer than 2.5 A for series connection. 3.33 A for a parallel connection. Assuming current is flowing into the positive terminal of the resistors.

Answer 3

this will depend if the resistors are in series or parallel. an easy way to tell if its series or parallel is to check if there is one loop or two loops created by the wire. if there is one loop it is series, if there are two loops its parallel.

also this question is hard to answer without knowing what ' f ' is

If its series:

1. work out the equivelent resistance:

Req = R1+R2

Req = 12+4

Req = 16 ohms

2. work out the current using ohms law:

V = IR

rearrange:

I = V/R

I = 40/16

I = 2.5A (because there is only one loop in the circuit the currenthas only one path and so is equal in each component)

If its parallel:

we know that the voltage across each branch (resistor) is equal. hence we can find the current through the resistors using ohms law:

I = V/R

I1 = V/R1

I1 = 40/12

I1 = 3.33' A (across the 12 ohm resistor)

and: I2 = V/R2

I2 = 40/4

I2 = 10 A (across the 4 ohm resistor)

to find the current through the generator:

both currents from R1 and R2 combine hence

Igen = I1+I2

Igen = 3.33'+10

Igen = 13.33 A (current through the generator)

alternitively to find the cuffent through the generator:

1. work out equivelent resistance:

Req = (R1*R2)/ (R1+R2)

Req = (12*4)/(12+4)

Req = 3 ohms

2. use ohms law on the generator:

Igen = V/Req

Igen = 40/3

Igen = 13.33' A

Answer 4

The question is not clear on whether the two 'devices' are in series or in parallel across the generator. If they are in series: The total effective resistance is (12 + 4) = 16 ohms, and the current is (40 / 16) = 2.5 Amp. If they are in parallel: The total effective resistance is [ 1 / (1/12 + 1/4) ] = (12 x 4) / (12 + 4) = 3 ohms, and the current is (40/3) = 13 and 1/3 Amp.

Answer 5

If the two devices are in series, then the resistance of the pair is 12 + 4, or 16 ohms. By Ohm's law, the current through the pair is 40 / 16, or 2.5 amperes and the coltage across the first device is 2.5 * 12, or 30 volts. In this case, by Kirchoff's current law, the current through the first device is the same as the current through the second device. If the two devices are in parallel, then the voltage across both devices is 40 volts. By Ohm's law, the current would be 40 / 12, or 3.33 amperes. In this case, by Kirchoff's voltage law, the resistance of the second device does not affect the current through the first device.