Q4 M8 - ELECTRICITY

In which of the following units is electrical consumption measured by electric companies for our household consumption in our homes?

• kilowatt
• megawatt
• volt
• kilowatt hour

In power stations generating electricity, power is measured in ________.

• joule
• kilojoule
• kilowatt
• megawatt

Why do power stations generate AC, and not DC? Because _____

• transformers work with AC.
• AC is more efficient and economical.
• AC is used in mobile devices and gadgets.
• it is easier to generate, safer, and more economical to transmit AC than DC.

Transformers are used to raise the voltage along substations and lower it for residential consumption. What kind of transformer is used to raise the voltage?

• Step-down
• Step-up
• Neither of the two.
• Both

Shayne turned on a lamp switch in her room. Which of the following is the correct path of electrical power that can be traced back to the source?

• distribution substations → transmission substations → power plants → residences
• power plant → transmission substations → distribution substations → residences
• residences → distribution substations → power plants → transmission substations
• transmission substations → power plants → residences → distribution substations

If a 100 W light bulb is lit for 8 hours each day for 20 days in a month. How many kilowatt-hours will the bulb consume?

• 16
• 160
• 1600
• 16000

What energy transformation takes place in a generator?

• chemical to mechanical
• heat to mechanical
• electrical to mechanical
• mechanical to electrical

You made an electric motor in school. When you tested it using 4 dry cells, the armature turned very fast. What should you do to make it turn slower?

• use a bigger magnet
• remove one of the dry cells
• increase the number of turns in the coil of wire
• decrease the distance between the magnetic poles

Gemma wanted to improve the lighting condition of her room by buying a lamp. What suggestions can you give her and why?

• Buy an incandescent bulb because it is cheaper.
• Buy an incandescent bulb because it gives off more light.
• Buy a fluorescent lamp because it is brighter than an incandescent bulb.
• Buy a compact fluorescent lamp (CFL) or LED lamp because it is more energy efficient.

Last month, Ms. Alcantara’s electric meter reads 8765 kWh. How much will she pay for power generation if the charge of the electric company per kWh is 6.88 pesos and her electric meter reads 9975 this month?

• ₱ 1, 210
• ₱ 3, 457.42
• ₱ 8, 324.8
• ₱ 8, 765