Answer:
4 times greater
Explanation:
<u>Step 1:</u> Calculate light-collecting area of a 20-meter telescope (A₁) by using area of a circle.
Area of circle = π*r² =
Where d is the diameter of the circle = 20-m


A₁ = 314.2 m²
<u>Step 2:</u> Calculate light-collecting area of a 10-meter Keck telescope (A₂)

Where d is the diameter of the circle = 10-m

A₂ = 78.55 m²
<u>Step 3</u>: divide A₁ by A₂

= 4
Therefor, the 20-meter telescope light-collecting area would be 4 times greater than that of the 10-meter Keck telescope.
<span>Frequency of a sound wave is called the pitch. Higher frequencies have a higher pitch and lower frequencies have the opposite. When an ambulance travels by a listener, the frequencies are oscillating rapidly and causing the shrill, loud sounds that emanate from the sirens.</span>
Answer:
Nuclear Reaction
Explanation:
Technically fusion and fission should be included, but a nuclear reaction includes both fusion and fission, so it must be the answer.