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saveliy_v [14]
2 years ago
9

The info below shows three kettles with their powers and the time they take to boil 500cm3 of water. If electricity costs 9p per

unit, how much does it cost to boil 500cm3 of water using the 3kW kettle?
Kettle 1= 3mins =3kW
Kettle 2= 3.5mins= 2.2kW
Kettle 3=4.5mins=1.4kW
Any help would be appreciated!
Physics
1 answer:
Hitman42 [59]2 years ago
5 0

The cost of boiling 500cm3 of water using the 3kW kettle is 1.35 P.

<h3>Cost of electricity for 3 kW kettle</h3>

The cost is calculated as follows;

1 unit = 9p /kWh

Total energy consumed by 3 kW kettle, E = P x t

where;

  • P is power (kW)
  • t is time in (hr)

E = 3 kW x (3 mins/60 mins/hr)

E = 0.15 kWh

Energy cost = 9 p/kWh x 0.15 kWh = 1.35 P

Thus, the cost of boiling 500cm3 of water using the 3kW kettle is 1.35 P.

Learn more about energy cost here: brainly.com/question/13795167

#SPJ1

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weqwewe [10]

Answer:

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(2)

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T_4 = \frac{1383.002}{2.702} =511.859 \ k

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c_v(T_4-T_1)  = 0.718×(511.859 - 290.15) = 159.187 kJ/kg

The efficiency is given by the following relation;

\eta = 1-\frac{\beta ^{k}-1}{\left (\beta -1  \right )r_{v}^{k-1}}

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β = Cut off ratio

Plugging in the values, we get;

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Heat supplied = \frac{150}{0.5191}  = 288.978 \ hp

Therefore, heat supplied = 215491.064 W

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Answer:

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