P3.1.2 - Your House (Light bulbs and LDRs) Flashcards

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1
Q

What is meant by ‘efficiency’?

A

Efficiency tells you the percentage of energy that does what you want, rather than what you do not want.

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2
Q

Old fashioned, incandescent light bulbs were not very energy efficient. This is because most of the energy they released was waste ________ energy.

A

thermal (heat)

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3
Q

Is it possible for an electrical appliance to be 100% efficient?

A

No - some waste heat energy is always released.

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4
Q

What is the equation that we use to calculate energy efficiency?

A
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5
Q

Currently the most efficient light bulb is called a…

A

Light Emitting Diode (L.E.D)

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6
Q

What does L.E.D stand for?

A

Light Emitting Diode

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7
Q

What is a sensor?

A

An electrical component that can detect changes in the surroundings (e.g. light levels)

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8
Q

What does LDR stand for?

A

Light Dependent Resistor

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9
Q

What is this the circuit symbol for?

A

Light Dependent Resistor (LDR)

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10
Q

A circuit that contains a sensor is called a…

A

sensing circuit

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11
Q

What happens to the electrical resistance of a light dependent resistor in high light levels?

A

The resistance of the LDR is low so electricity can pass through it.

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12
Q

What might you use an LDR for?

A

To control the light level in a room

Lamp posts

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13
Q

Which is more energy efficient; an incandescent light bulb or an LED?

A

LED

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14
Q

In what form is waste energy usually?

A

Heat

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