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Chapter 24: Problem 30

A watch uses energy at the rate of \(240 \mu \mathrm{W}\). What current does it draw from its \(1.5-\mathrm{V}\) battery?

Short Answer

Expert verified
The current drawn by the watch from its battery is approximately \(1.6 \times 10^{-4} \mathrm{A}\) or 0.16 \(\mu A\).

Step by step solution

01

Conversion of Power

Since the power given is in \(\mu W\) (micro watts), it needs be converted into watts (W). Currently, the power \(P = 240 \mu \mathrm{W} = 240 \times 10^{-6} \mathrm{W}\)
02

Apply Ohm's Law

Ohm's Law states that 'The current drawn, I is equal to the power used, P divided by the voltage used, V'. Therefore, apply Ohm's Law, \(I = P / V\)
03

Calculate the Current

Substitute the given values P = 240 x \(10^{-6} \mathrm{W}\) and V = 1.5 V, in the formula \(I = P / V \) to find the current I in amperes.
04

Final Result

The calculation will yield \(I = (240 \times 10^{-6} \mathrm{W}) / 1.5 \mathrm{V}\). Solving the expression will give the current drawn by the watch in amperes.

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