Activity 3.10 Physics F5

3.4 Electrical Energy and Power

Activity 3.10

Name: Liow Yee Shuen
Class: 5 Balau
Aim: To calculate electrical energy consumption

at home

No. ELECTRICAL quantity power / kw hours used total energy
APPLIANCES (a) (b) in a day / h usage / kwh
(c) (a x b x c)

1. electric rice 1 0.950 1.0 0.950
cooker 1 0.013 1.0 0.013

2. lamp

3. air fryer 1 1.425 0.5 0.713

4. laptop adapter 3 0.065 6.0 1.170

6. ceiling fan 2 0.072 4.0 0.576

7. air conditioner 3 0.500 3.0 4.500

9. stand fan 1 0.050 2.0 0.100

10. light bulb 11 0.060 5.0 3.300

11. fridge 1 0.100 24 2.400

12. vacuum 1 0.400 1.0 0.400

13. washing machine 1 0.500 2.0 1.000

Total energy usage in a day / kWh 15.122

(a) Estimate the energy usage in kWh for 30 days.

15.122 kWh X 30 days
= 453.66 kWh

(b) Base on your home electricity bill, complete the following table
(with the relevant information):

Tariff block (kWh) Prorated block (kWh) Rate (RM) Amount (RM)

200 200 0.218 43.60

100 100 0.334 33.40

300 153.66 0.516 79.29

Total 156.29

(c) Compare the estimated cost for one month with the real cost of
the electricity usage found in your monthly bill.

Estimated Cost for
One Month:

RM 156.29

Actual Cost for one
month:

RM 159.56

The estimated cost
for one month is
lesser than the actual
cost for one month
due to the inaccurate
estimated hours
used of electrical
appliances in a day.

Discussion:

1. Identify the electrical appliance in your home that consumes the highest
electrical energy.

Air conditioner.

2. Suggest steps to reduce the cost of electricity consumption in your home.

- Turn off unnecessary lights
- Use natural light
- Unplug unused electronics
- Wash laundry in cold water
- Wash full loads of laundry

eenndd-------- ---------