Laser facts & stats

Question 1

Compared with a flashlight beam, what does a laser beam typically do?

Accepted Answer

Stays narrow and spreads very little. Laser light is highly directional, so the beam stays narrow over long distances instead of spreading like a flashlight.

Question 2

Which kind of player reads music from a disc using a laser?

Accepted Answer

CD player. A CD player's laser reads tiny pits in the disc; a record player uses a needle.

Question 3

In what year was the first working laser demonstrated?

Accepted Answer

1960. Theodore Maiman demonstrated the first working laser in 1960.

Question 4

What does it mean that laser light is 'monochromatic'?

Accepted Answer

It has a single color or wavelength. Monochromatic means one color; laser light is concentrated in a very narrow band of wavelengths.

Question 5

What color is the beam of a common helium-neon laser?

Accepted Answer

Red. Helium-neon lasers usually emit red light at a wavelength of about 633 nanometers.

Question 6

Which device works on the same principle as a laser but with microwaves, and came first?

Accepted Answer

Maser. The maser, microwave amplification by stimulated emission of radiation, was built in the 1950s.

Question 7

Scientists bounce lasers off reflectors left on the Moon by which missions?

Accepted Answer

Apollo missions. Apollo astronauts left retroreflectors that let scientists measure the Earth-Moon distance very precisely.

Laser facts & stats

The basics