Question 1144681: The energy 𝑊 used by a device is directly related to the current 𝐼, the voltage 𝑉, and the length
of time 𝑡, for which the energy is used. If a 240-V clothes drier draws a current of 15 A and in 45
min uses 2.4 kWh (kilowatt hours) of energy, how much energy will a 120-V light bulb use, which
draws a current of 1.25 A in 8 h of use?
Answer by ikleyn(52781)   (Show Source):
You can put this solution on YOUR website! .
The energy 𝑊 used by a device is directly related to the current 𝐼, the voltage 𝑉, and the length
of time 𝑡, for which the energy is used. If a 240-V clothes drier draws a current of 15 A and in 45
min uses 2.4 kWh (kilowatt hours) of energy, how much energy will a 120-V light bulb use, which
draws a current of 1.25 A in 8 h of use?
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At 240 V, 15 A and 45 minutes the energy is NOT 2.4 kWh.
It is 240*15*0.75 =2.7 kWh.
It means two things.
(a) You provide WRONG data, and
(b) You do understand NOTHING in the subject.
At given circumstances, I do not see any reason to discuss the subject further with you.
PERIOD.
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The third thing is that when the second cluster of input data is given to you, you can calculate the energy directly
by multiplying three values of the second cluster.
The energy, by the definition of these units, is their product W = I*U*t.
The referring "if - then" from the second cluster to the first cluster is UNNECESSARY and INCORRECT.
The link (the connection) "if - then" does not work in this case and should not even be used.
The entire problem demonstrates TOTAL INCOMPETENCE of the author of this problem in the subject.
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