Chapter 1.8 Electrical appliances Flashcards
1
Q
What form do electrical appliances transfer energy?
A
Electrical appliances can transfer energy in the form of useful energy at the flick of a switch.
2
Q
What do the uses of everyday electrical appliances include?
A
- Heating
- Lighting
- Making objects moving (using electric motor)
- Producing sound and visual images
3
Q
Name the useful energy of these appliances:
- Light bulb
- Electric heater
- Electric toaster
- Electric kettle
- Hair dryer
- Electric motor
A
- Light bulb - light emitted from the glowing filament
- Electric heater - Energy heating the surroundings
- Electric toaster - Energy heating bread
- Electric kettle - Energy heating water
- Hairdryer - Kinetic energy of the air driven by the fan and energy heating the air flowing past the heater filament.
- Electric motor - Kinetic energy of objects driven by the motor and gravitational potential energy of objects lifted by the motor.
4
Q
Name the wasted energy of these appliances:
- Light bulb
- Electric heater
- Electric toaster
- Electric kettle
- Hair dryer
- Electric motor
A
- Light bulb - Energy transfer from the filament heating the surroundings
- Electric toaster - Light emitted from the glowing element
- Electric toaster - Energy heating the toaster case and the air around it
- Electric kettle - Energy heating the kettle itself
- Hairdryer - Sound of fan motor and energy heating the hairdryer itself
- Electric motor - Energy heating the motor and energy transferred by the sound waves generated by the motor.
5
Q
What is electricity a flow of?
A
Electricity is not an energy store, but rather is a flow of charge that transfers energy from one energy store to another.
6
Q
What is the definition of efficiency?
A
Efficiency is a measure of how much work or energy is conserved in a process. In many processes, work or energy is lost. A perfect process would have an efficiency of 100%.
