Consider the circuit shown in (Figure 1). Suppose that ΔV = 7.5 V. What is the value of resistor R?

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  • 1 month ago
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    total R = E/I = 7.5/0.1 = 75 Ω

    R = 75 – 10 – 15 = 50 Ω

  • 1 month ago

    Ohm's law "E = IR" translates to:

        7.5 = (0.100)(10 + 15 + R)    . . . . in volt, amp, ohm units

        75 = 25 + R

        R = 50 (ohms)

    The important step was to write I in ampere units instead of mA, to get units in a syste where there's no coefficient needed for Ohm's law.  You could also use (mV, mA, ohms) or (volt, mA, K-ohms) as common choices.

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