In electron-volts, how much work does an ideal battery with a 36.0 V emf do on an electron that passes through the battery from the positive to the negative terminal? (b) If 7.56 × 1018 electrons pass through each second, what is the power of the battery?

(a) 36 eV

(b) 43.2 Watt

Explanation:

(a)

We, know that:

Potential Difference = Work/Charge

Work = (P.d)(Charge)

for one electron,

charge = 1.6 x 10⁻¹⁹ C

Therefore,

Work = (36 V)(1.6 x 10⁻¹⁹ C)

Work = (57.6 x 10⁻¹⁹ J)(1 eV/1.6 x 10⁻¹⁹J)

Work = 36 eV

(b)

First we find the current passing through battery.

Current = Charge/Time

Current = I = (No. of electrons)(Charge on one electron)/Time

I = (7.56 x 10¹⁸ electrons)(1.6 x 10⁻¹⁹ C/electron)/ 1 sec

I = 1.2 A

Now, for power:

P = VI

P = (36 V)(1.2 A)

P = 43.2 Watt

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