Question

Calculate the Energy Consumed per
day when an Electric Iron of
1200watts is used for a period of 20minutes.
O 1.4units
O 0.4units
O 1kwhr
O 2kwhr​

Answer 1

Explanation:

1200 W for 0.5 h can consume 1200* 0.5 =600 Wh = 0.6 kWh of energy per day of use.

April has 30 days.

Thersfore total energy consumption during this period = 0.6* 30 = 18 kWh.

It should be noted that this figure is the maximum energy consumption.

Actual energy consumption would be considerably less than this on account of the thermostat tripping when the set temperature is attained, and keeping the device off till it becomes cool enough to get switched on again

Answer 2

Given

An Electric Iron of  1200 Watts is used for a period of 20 minutes

To Find

Energy consumed per day

Solution

We know that

$\rm \longrightarrow E=Pt$

Here

• E = Energy
• P = Power
• t = Time

Units

• E = kWh = Units
• P = Watt (W)
• t = hour (h)

According to the question

We are asked to find energy consumed per  day

Therefore

We must find "E"

Given that

An Electric Iron of  1200 Watts is used for a period of 20 minutes

Hence

• P = 1200 W
• t = 20 m = 0.333 h

Substituting the values

We get

$\rm \longrightarrow E=1200 \times 0.333 \ Wh$

$\rm \longrightarrow E=399.6 \ Wh$

$\rm \longrightarrow E=0.399 \ kWh$

$\rm \longrightarrow E \approx 0.4 \ kWh$

Therefore

$\rm \longrightarrow E=0.4 \ units$

Hence

Energy consumed per day = 0.4 units

So

Option (2) is correct