Teachers’ Guide
Lesson Plans: Physics
Cost = Power (in watts) x time (in hours) x No. of days x cost of one unit (kWh) 1000 Activity 2 Teacher asks the students to carry out an extensive survey of electrical appliances at their homes. In their survey they collect the information and complete the given table. If cost of one electrical energy unit = Rs.5 Appliances
No. of Appliances
Power Rating
Estimated Usage (hour per day)
Energy Consumed
Cost of Energy
Average Monthly Electric Bill
Bulb Fan T.V Total
Activity 3 Hang the following information sheet in the class on the board and ask the following question to the students: Q1: What is the standard voltage supply in Pakistan? Ans: 220 volts Q2: What is the standard voltage at which all the electrical appliances work properly? Ans: 220 volts Q3: Which appliance use, the highest electrical energy? Ans: Electric Oven Q4: Which appliances should be used at the minimum to reduce monthly bill? Ans: Electric oven, Electric heater, geyser and electric kettle
57
Appliances
Power Voltage Rating of Rating of Appliances Appliances (in w) in Volt 15 – 200
220
Tube Light
40
220
Electric Fan
60 – 100
220
T.V
120
220
Electric Iron
750
220
Room Heater
1000
220
Geyser
1500
220
Electric Kettle
2000
220
Electric Oven
3000
220
Bulb