Energy Efficiency

The video tutorial explains the concept of energy use and waste, highlighting that while energy cannot be created or destroyed, its usefulness can be diminished as it dissipates as waste heat. It uses a food mixer as an example to illustrate energy transfer, where only movement is useful, and sound and heat are wasted. The tutorial also covers how to visualize energy efficiency using diagrams and compares the efficiency of filament and LED bulbs, showing why LEDs are preferred. It concludes with methods to improve energy efficiency, such as using insulation and reducing friction.

What happens to the energy once the food is mixed in a food mixer?

• It is scattered as sound and heat, warming the surroundings.

• It is completely converted into sound energy.

• It is stored in the mixer for future use.

• It remains in the food as potential energy.

How efficient is an old-fashioned filament bulb compared to an LED bulb?

• Filament bulbs are more efficient than LEDs.

• Filament bulbs are equally efficient as LEDs.

• Filament bulbs are less efficient than LEDs.

• Filament bulbs do not use any energy.

What is the formula to calculate the efficiency of a device?

• Efficiency = Useful energy transferred / Total energy supplied x 100

• Efficiency = Total energy supplied / Useful energy transferred x 100

• Efficiency = Total energy supplied / Wasted energy x 100

• Efficiency = Wasted energy / Useful energy transferred x 100

Which method can reduce the transfer of energy to heat due to friction?

• Using thicker wires

• Using more powerful motors

• Increasing the speed of operation

• Applying lubrication

What is one way to reduce heat loss in a house?

• Using single-pane windows

• Leaving doors open

• Installing double glazing

• Removing insulation from walls