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A television using 1,000 W of power is turned on for 40 minutes.  How much energy is expended by the television during this time?
in Grade 12 Physical Sciences by Diamond (39.7k points) | 34 views

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There are 2 questions on this page, I'm answering the one:
A hair dryer with a resistance of 30 Ω is plugged into a 120-volt socket. If the hair dryer is used for 10 minutes, how much electrical energy is used?

R = 30 Ω                            W = V²t / R

V = 120 V                               = (120)² (600) / 30

t = 10 * 60 (600s)                    = 288 000 J

by Wooden (734 points)
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E= P*t

=(1.000)*(40*60)

=(1.000)* (2400)

=2400 J
by Wooden (2.3k points)
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E = Pt in Joules per second

=1000x40x60

=2,400,000 J/s
by Wooden (1.1k points)
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The power is not 1000 W but 1 W and the units for energy is not J/s rather W.s which is equivalent to J.

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