Question

question 4
a spectroscope is used to identify elements in a star.
true
false
question 5
groups of radio telescopes that work together are called masers.
true
false
question 6
the light - gathering power of a lens varies with the square of its radius.
true
false

Explanation:

• Question 4: A spectroscope analyzes the spectrum of light from a star. Each element has a unique spectral - fingerprint, allowing identification.
• Question 5: Masers are devices that amplify and emit microwaves or radio waves. Groups of radio telescopes working together are called interferometers.
• Question 6: The light - gathering power of a lens is proportional to the area of its aperture, and since the area of a circle is $A=\pi r^{2}$, it varies with the square of its radius.

Answer:

Question 4: True
Question 5: False
Question 6: True