Choose the correct alternative

1. Which of the following light sources does not use electricity?

LED
fluorescent lamp
incandescent light bulb
candle
halogen lamp

2. What is the light source of an incandescent light bulb?

semiconductor
fluorescent material
glass
gas
heat resistor

3. What is the (visible) light source of a fluorescent lamp?

semiconductor
heat resistor
fluorescent material
glass
gas

4. Which of the following metals produces the light of a fluorescent lamp?

gold
silver
copper
mercury
platinum

5. What is the chemical sign of mercury?

Eu
Au
Ag
Hg
Eh

6. What is the light source of an LED lamp?

heat resistor
semiconductor
fluorescent material
glass
gas

7. Why should incandescent light bulbs be replaced with other kinds of light bulbs?

They do not provide enough light.
They break easily.
They produce too much heat..
They are difficult to recycle.
They are expensive.

8. What is the advantage of LED lamps?

They are cheap.
They do not produce waste.
They are resistant to heat.
They are long-lasting.
They come in nice packages.

9. Which of the following wavelengths of light is invisible to humans?

blue-red
infrared
red
blue
white

10. What is the disadvantage of fluorescent light bulbs?

They use up a lot of electricity.
They are expensive.
They do not produce good-looking light.
They heat up easily.
They are hard to recycle.