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2 years ago

8

A cell phone charger operates at 5 volts and can deliver a maximum current of 1.0 Amp. If your cell phone has an energy storage

capacity of 38.9~38.9 kiloJoules, what is the shortest possible time (in hours) it would take to fully charge your empty phone battery using this charger.

1 answer:

madam [21]2 years ago

7 0

Answer:

<em>it</em><em> </em><em>takes</em><em> </em><em>2</em><em>.</em><em>1</em><em>6</em><em> </em><em>hrs</em><em> </em><em>to</em><em> </em><em>fully</em><em> </em><em>charge</em><em> </em><em>the</em><em> </em><em>phone</em>

Explanation:

V = 5v

I = 1A

E = 38.9 Kj = 38900 j

t = ?

E = IVt

t = E/IV

t = 38900 ÷ (1 × 5)

t = 38900 ÷ 5

t = 7780 seconds

t = 7780/3600............( converting time in seconds to hours)

t = 2.16 hrs

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3 years ago

A 10 gauge copper wire carries a current of 20 A. Assuming one free electron per copper atom, calculate the magnitude of the dri

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Complete Question

A 10 gauge copper wire carries a current of 20 A. Assuming one free electron per copper atom, calculate the drift velocity of the electrons. (The cross-sectional area of a 10-gauge wire is 5.261 mm2.) mm/s

Answer:

The drift velocity is $v = 0.0002808 \ m/s$

Explanation:

From the question we are told that

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The cross-sectional area is $A = 5.261 \ mm^2 = 5.261 *10^{-6} \ m^2$

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So

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$n = 8.46 * 10^{28} \ atoms /m^3$

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3 years ago

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