Question #350636

Resistor consist of R1=4, R2= 4.5 R3= 12

Resistor R3 connected in parallel with R2 .

1 )draw a the circuit diagram

2 )calculate the voltage across R3 if the applied voltage is 12V .

3 ) calculate the current passing R1 and R 3

Expert's answer

**Solution:**

Some notes: in the given of problem there is not full information about how R1 connected to the circuit. That's why I will try to find solutions as example.

1) See attach image for some possibility of circuit diagrams.

2) We will find voltage via R3 according to 1 diagram.

Let's find total resistance of circuit:

"R_{23}=\\frac{R_2R_3}{R_2+R_3}=\\frac{4.5\\times12}{12+4.5}=3.3;"

"R=R_{23}+R_1=3.3+4=7.3;"

So, total current of circuit:

"I=\\frac{U}{R}=\\frac{12V}{7.3}\\Omega=1.64A;"

From Krich's rule:

"I_2R_2=I_3R_3; \\space and \\space I_3+I_2=I;"

"I_3=\\frac{R_2}{R_2+R_3}\\times I=\\frac{4.5}{4.5+12}\\times 1.64=0.45A;"

"U_3=I_3R_3=0.45A\\times12\\Omega=5.37V."

3) For 1 diagram:

"I_1=I=1.64A;"

"I_3=0.45A."

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