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Question 12 of 20:
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12. A series circuit contains three resistors. You measure the voltage drop across each resistor and then add the three measurements together for a total of 18 VDC. The current in
the circuit measures 1.2 amps. What's the supply voltage?
O A. 15 VDC
O B. 20 VDC
O C. 24 VDC
O D. 18 VDC
251 PM
12/31/2022

User Bradvido
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1 Answer

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we need to use Ohm's law: V = IR, where V is the voltage, I is the current, and R is the resistance.

Since we know the total resistance of the circuit is equal to the sum of the resistance of the three resistors, we can find the total resistance by dividing the total voltage drop (18 V) by the current (1.2 A):

R = V/I = 18 V / 1.2 A = 15 ohms

Since we know the total resistance and the current in the circuit, we can use Ohm's law to find the supply voltage:

V = IR = 1.2 A * 15 ohms = 18 V

Therefore, the supply voltage is 18 VDC. The correct answer is therefore D) 18 VDC.
User Conrad Frix
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6.3k points