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This is an electricity question. What is the total resistance and current? what is the...

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t4trendesetter | Honors

Posted June 15, 2013 at 8:38 AM via web

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This is an electricity question.

What is the total resistance and current?

what is the voltage over R2?

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Mary Joy Ripalda | High School Teacher | (Level 3) Educator

Posted June 15, 2013 at 9:19 AM (Answer #1)

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(A) Total Resistance

To compute, determine if the resistors are connected in series or parallel.

Base on the figure above, R1 and R2 are connected in series. And when resistors are in connected in series, their total resistance is the sum of their corresponding values.

`R_T=R_1+R_2=20+100`

`R_T=120`

Hence, the total resistance is 120 ohms.

(B) Total Current

To solve, apply Ohm's Law formula which is:

`V=IR`

Then, manipulate the formula such that I is isolated on one side of the equation.

`I=V/R`

However, circuit's connection must be considered. Since it is in series, the current that passes through R1 and R2 are the same.

So to compute for the total current, use the supply voltage for V and total resistance for R in the formula.

`I_T= V_S/R_T=12/120`

`I_T=0.1`

Thus, the total current is 0.1 ampere.

(C) Voltage over R2

Note that in series circuit, the current in each load are the same. But, the voltage are different.

So to solve for the voltage across R2, plug-in the total current and the value of R2 to Ohm's Law formula.

`V_2=I_TR_2=0.1*100`

`V_2=10`

Hence, the voltage across R2 is 10 volts.

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