Answer:
L = 0.7 m
Explanation:
This is a resonance exercise, in this case the air-filled pipe is open at both ends, therefore we have bellies at these points.
λ / 2 = L 1st harmonic
λ = L 2nd harmonic
λ = 2L / 3 3rd harmonic
λ = 2L / n n -th harmonic
the speed of sound is related to wavelength and frequencies
v =λ f
f = v /λ
we substitute
f = v n / 2L
the speed of sound in air is v = 343 m / s
suppose that the frequency of f = 980Hz occurs in harmonic n
f₁ = v n / 2L
f₂ = v (n + 1) / 2L
f₃ = v (n + 2) / 2L
we substitute the values
2 980/343 = n / L
2 1260/343 = (n + 1) / L
2 1540/343 = (n + 2) / L
we have three equations, let's use the first two
5.714 = n / L
7.347 = (n + 1) / L
we solve for L and match the expressions
n / 5,714 = (n + 1) / 7,347
7,347 n = 5,714 (n + 1)
n (7,347 -5,714) = 5,714
n = 5,714 / 1,633
n = 3.5
as the number n must be integers n = 4 we substitute in the first equation
L = n / 5,714
L = 0.7 m
<span>This is known as a "solar eclipse." The Moon partially or completely covers the Sun, leading to a rapidly moving shadow across the sunlit face of the Earth.</span>
Answer:
There are 45 turns in the secondary coil.
Explanation:
Given that,
Input potential of the lamp, 
The output potential of the lamp, 
Number of turns in primary coil, 
We need to find the number of turns needed on the secondary coil. We know that the ratio for a transformer is as follows :

So, there are 45 turns in the secondary coil.
Hermes has a rotating wheel, or centrifuge, to provide artificial gravity for the crew. Spaceships in “2001: A Space Odyssey” and “Mission to Mars” were similarly equipped. Although it is not shown in the film, the astronauts would have used a Mars descent vehicle (MDV) to get down from Hermes to the surface.