DCA 4 Universe

Why do stars look brighter or dimmer in the sky?

• Age of the Star

• Orion has the brightest stars

• distance - you can't tell how far away stars are when looking from Earth

• Tha shape of the Star.

Astronomers observed a bright object with a fan-shaped tail.

• comet

• An asteriod

• A meteor

• A nebula

Regulus is a star with a temperature of 10,300 K what spectral does Regulus belong to?

• Spectral class O

• Spectral class B

• Spectral class A

• Spectral class M

The frequency of infrared waves is..

• 10¹² Hz
• 10²⁰ Hz
• 10⁴ Hz
• 10¹⁵ Hz

What is the correct order of the visible light spectrum starting with the longer wavelength?

• Red, yellow, orange, blue, violet, indigo

• Violet, indigo, blue, green, yellow, orange, red

• Green, yellow, blue, indigo, red, orange

• Red, orange, yellow, green, blue, indigo, violet

What gases are in the unknown mixture?

• Gas B & Gas D
• Gas C & Gas B
• Gas A & Gas D
• Gas D & Gas C

Scientists observed a celestial object emitting a wavelength of 3 x 10^-10m. What type of telescope did the scientists have to use to view this?

• Radio wave

• Infrared ray

• X-ray

• Gamma Ray

Scientists observed a celestial object emitting waves with a frequency of 1.41 x 10⁸ Hz. What type of telescope did the scientists have to use to view this object?

• Radio wave

• Microwave

• X-ray

• Ultraviolet wave

The Sun is a medium-star and many stars are bigger and brighter. When looking through a telescope why do the other stars seem more dim than the Sun?

• Yellow is more visible than other colors

• The Sun is closer than the other stars

• They are made up of different gases

• light from stars travels through space and is reflected

True or False

When compared to the Sun, Star W has a lower luminosity?

• True

• False