P3.1.2 - Your House (Light bulbs and LDRs) Flashcards
What is meant by ‘efficiency’?
Efficiency tells you the percentage of energy that does what you want, rather than what you do not want.
Old fashioned, incandescent light bulbs were not very energy efficient. This is because most of the energy they released was waste ________ energy.
thermal (heat)
Is it possible for an electrical appliance to be 100% efficient?
No - some waste heat energy is always released.
What is the equation that we use to calculate energy efficiency?
Currently the most efficient light bulb is called a…
Light Emitting Diode (L.E.D)
What does L.E.D stand for?
Light Emitting Diode
What is a sensor?
An electrical component that can detect changes in the surroundings (e.g. light levels)
What does LDR stand for?
Light Dependent Resistor
What is this the circuit symbol for?
Light Dependent Resistor (LDR)
A circuit that contains a sensor is called a…
sensing circuit
What happens to the electrical resistance of a light dependent resistor in high light levels?
The resistance of the LDR is low so electricity can pass through it.
What might you use an LDR for?
To control the light level in a room
Lamp posts
Which is more energy efficient; an incandescent light bulb or an LED?
LED
In what form is waste energy usually?
Heat
