The meter reads 7.84 mA when the switch is in position A. What is the resistance of R4?
R1=220 Ω
R2=470 Ω
R3=510 Ω
VS =12 V
I honestly have no clue how to solve this. Please help.
I honestly have no clue what your circuit looks like.
My fault. It's figure 73 (one on left).
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Rt = Vs/I = 12/7.84ma = 1.53k Ohms = 1530 Ohms = Total resistance.
R4 = Rt-(R1 + R2 + R3) = 1530 - 1200 = 330 Ohms.
To find the resistance of R4, we need to apply Ohm's Law, which states that the current (I) flowing through a resistor is equal to the voltage (V) across the resistor divided by the resistance (R): I = V/R.
In this problem, we are given the current (I) as 7.84 mA (milliamperes) when the switch is in position A. However, before we can calculate the resistance of R4, we need to determine the total resistance (RT) in the circuit.
The circuit diagram is not provided, so we will assume that R4 is in series with R1, R2, and R3. In a series circuit, the total resistance is the sum of the individual resistors:
RT = R1 + R2 + R3 + R4
Now, let's assign values to R1, R2, and R3, which are given in the problem:
R1 = 220 Ω
R2 = 470 Ω
R3 = 510 Ω
To determine the resistance of R4, we need to compute the total resistance (RT) using the above equation. Then we can isolate R4:
RT = R1 + R2 + R3 + R4
R4 = RT - R1 - R2 - R3
Next, we need to find the total resistance (RT) of the circuit. Since the circuit's voltage source (VS) and the current passing through the circuit are known, we can use Ohm's Law to find the total resistance:
VS = I * RT
Given that the voltage source (VS) is 12 V and the current (I) is 7.84 mA (0.00784 A), we can rearrange the equation to solve for RT:
RT = VS / I
Substituting the values:
RT = 12 V / 0.00784 A
Calculating this value will give us the total resistance (RT). Once we have the total resistance, we can substitute it into the equation to find the resistance of R4:
R4 = RT - R1 - R2 - R3
With these calculations, you should be able to find the resistance of R4.