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Electrical Energy

Rural Technology

Capacity for doing work is called energy. That means energy required for electrical work done in a particular time period is called electrical energy. Its symbol is ‘E’. The unit of electrical energy is kilowatt hours and its symbol is Kwh. If 1 kwh power is used in 1hour the energy consumed is 1 kilowatt hour. Or Board of Trade Unit ( B.O.T.V.)

Where,
Kwh = Kilowatt in units
E = E.m.f, in volt
I = Current in ampere
h = hour Ex. 1 A motor running on 230-v mains is takes 35 amperes current, for period of 50 hours per week. If the cost of power is Rs. 4 per unit find the cost of running, this motor for 5 hours working.

= 402.5 units.
Bill = Kwh ´ Rate per unit
= 402.5 ´ Rs. 4 = Rs. 1610

Intext Questions 4.3
1. What is energy?

2. A motor running on 230V. Mains take 80 amperes current from the mains. It is used 4 hours per day. If it is used 30 days & rate is
Rs. 3 per unit, calculate the bill.

What you have learnt

·

• In this unit you have learnt about basic terms of electricity.
• · Basic term of current its symbol, unit.
• · Basic term of EMF & its symbol unit.
• · Connection of Ammeter & voltmeter.
• · Definition of resistance & its unit.
• · Definition of power & its unit.
• · Definition of energy & its unit.
• · Simple examples of power & energy.

Terminal Questions

1. What is Matter? Explain in detail.
5. Write a short notes on the Following:
a) Atom
b) Molecule
c) Nucleus
d) Proton
e) Neuteron
f) Electron

1
a) Fill in the blanks:
1. Matter
2. Atom
3. Negative
4. Current
5. Ampere
b) True or False:
1. False
2. False
3. True
4. True
5. True 2
1. Power means rate of doing work.
2.

= 1Kw 3
1. Capacity for doing work is called energy.
2.

= 2208 units.
Bill = 2208 ´ Rs. 3
= Rs. 6624

Rural Technology