Energy and Electrical Energy

using electrical energy

By Mohamed Aboukamar

​NO	​Lesson Objectives
​1	​Define superconductors and demonstrate their importance
2​	​Explain how current in transmission lines is altered to reduce thermal energy transformations
3​	​Convert energy in joules to kWh and calculate the consumption and cost of (electrical energy used by different devices)

Loss of power

transformation of electrical energy

normal light bulb uses only 10% of its energy to make light! The other 90% is turned into heat. 

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Current moving through a resistor increases its thermal energy because flowing electrons bump into the atoms in the resistor

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​what is the reason of transformation?

​Symbol	​Mean	Unit​
P	​power	​W (Watt)
I​	Electric current​	A (Ampere)​
V​	Voltage​	V (volt)​
R​	Resistance​	ohms
E​	Electrical energy​	J (joule)​
t​	time​	​S (Second)

Multiple Choice

A heater has a resistance of 10 ohms. it operates of 120.0 V.

What is the power of the heater?

• 902 W

• 1440 W

• 550 W

• 860 W

. a material with zero resistance.

. almost all superconductors must be kept at temperatures below 100 K.

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Superconductors

Electrical energy is transformed at a rate represented by P = I²R.

1. By reduce current (I)

2. ​By reduce resistance of wire (R)​

How can the transmission occur with as little transformation to thermal energy as possible?

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Kilowatt hour

By calculate value of power, the value will be in watt that is large value so it must be converted to kilowatt by divide it 1000

Calculate value of power

convert given time to hours

by multiply power in KW with value of time in hour now you value of consumed electrical energy

calculate electrical energy

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Multiple Choice

 

If a 100W light bulb is lit for 8 hrs for 20 days, how many killowatt hours will the bulb consume?

• 16

• 160

• 1600

• 16000