A blow-dryer and a vacuum cleaner each operate with a voltage of 120 V. The current rating of the blow- dryer is 11 Amps, and that of the vacuum cleaner is 4.0 Amps. Determine the power consumed by (a) the blow-dryer and (b) the vacuum cleaner, (c) Determine the ratio of the energy used by the blow-dryer in 15 minutes to the energy used by the vacuum cleaner in one-half hour.

(a) 1320 W

(b) 480 W

(c) E':E ≈ 11:2

Explanation:

(a) Applying,

P' = VI' Equation 1

Where P' = Power of the blow-dryer, V = Voltage, I = current rating of the blow-dryer.

From the question,

Given: V = 120 V, I' = 11 A

Substitute these values into equation 1

P = (120×11)

P = 1320 W

(b) Similarly,

P = VI Equation 2

Where P = Power of the vacuum cleaner. I = current rating of the vacuum cleaner.

Also Given: I = 4 A,

Therefore

P = 4(120)

P = 480 W

(c)

E' = P'/t' Equation 3

E = P/t Equation 4

Where E' = Energy of the blow-dryer, t' = time of use of the blow-dryer, E = Energy of the vacuum cleaner, t = time of use of the vacuum cleaner

From the question,

Given: t' = 15 minutes = (15×60) = 900 seconds, t = 30 minutes = (30×60) = 1800 seconds

Substitute these values into equation 3 and 4

E' = 1320/900

E' = 1.47 J,

E = 480/1800

E = 0.267

Therefore,

E':E = 1.47:0.267

E':E ≈ 11:2

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