Question

A heater uses 20 A when used in a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is?

Answer 1

Answer:

$2.2

Explanation:

The power is the product of current and its voltage

P = UI = 110*20 = 2200 W or 2.2 kW

The total energy (in kwH) to run this heater for 10 hours

E = Pt = 2.2 * 10 = 22 kwH

If it costs 10 cents for every kwH, the total cost for running this heater for 10 hours is

C = 22 * 10 = 220 cents or 2.2 dollar

Answer 2

The cost of running the heater for 10 hours is 220 cents (i.e $ 2.2)

We'll begin by calculating the power. This can be obtained as follow

Current (I) = 20 A

Voltage (V) = 110 V

Power (P) =?

P = IV

P = 20 × 110

P = 2200 W

• Next, we shall convert 2200 W to KW.

1000 W = 1 KW

Therefore,

2200 W = 2200 / 1000

2200 W = 2.2 KW

• Next, we shall determine the energy in KWh. This can be obtained as follow:

Power (P) = 2.2 KW

Time (t) = 10 h

Energy (E) =?

E = Pt

E = 2.2 × 10

E = 22 KWh

• Finally, we shall determine the cost of running the heater for 10 h. This can be obtained as follow:

Energy (E) = 22 KWh

Cost per kWh = 10 cents

Cost for 10 h =?

Cost = Energy × Cost per kWh

Cost = 22 × 10

Cost = 220 cents = $ 2.2

Thus, the cost of running the heater for 10 hours is 220 cents (i.e $ 2.2)

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