Answer:
a. E = 900000 J = 900 KJ
b. ΔT = 8.18 °C
c. Cost = $ 7.2
Step-by-step explanation:
a.
The energy can be given by:
where,
E = Energy = ?
P = Power = 500 W
t = time = (0.5 h)(3600 s/1 h) = 1800 s
Therefore,
E = 900000 J = 900 KJ
b.
The change in temperature of room air is given by the following formula:
(since 50% of energy is used to heat air)
where,
m = mass of air = 50 kg
C = specific heat of air = 1.1 KJ/kg.°C
ΔT = Change in temperature of air = ?
Therefore,
ΔT = 8.18 °C
c.
First, we will calculate the total energy consumed:
Now, for the cost:
Cost = $ 7.2