Answer: • Visible Light, Radio Waves
• Radio - 305-m , at Arecibo, Puerto Rico
Visible Light - 10.4m Mirror, Canary Island
Explanation:
The spectral window is simply the range of frequencies that are correctly measured. It should be noted that the signals that are outside the spectral window are folded when they show up in spectrum.
The two spectral windows through which electromagnetic radiation easily reaches the surface of earth are the visible light and the radio waves.
Answer:
3.83 m/s
Explanation:
Given that,
Distance covered by Jan, d = 4 miles
1 mile = 1609.34 m
4 miles = 6437.38 m
Time, t = 28 minutes = 1680 s
Jan's average speed,
v = d/t

Hence, the average velocity of Jan is 3.83 m/s.
The potential energy of the block is A) 490 J
Explanation:
The potential energy of an object is the energy possessed by the object due to its position in the gravitational field.
It is calculated as follows:

where
m is the mass of the object
g is the acceleration due to gravity
h is the height of the object above the ground
For the block in this problem, we have:
m = 10 kg

h = 5 m
Therefore, its potential energy is:

Learn more about potential energy:
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Light from the stars, because the orbits make it difficult to see them.
Answer:
v = 1.30 m/s
Explanation:
given,
mass hung = 0.35 Kg
spring stretched when load is hanged (x)= 0.13 m
now,
weight of the mass attached = Kx
m g = k x
0.35 x 9.8 = k x 0.13
k = 26.38 N/m
now, using conservation of energy




v = 1.30 m/s