Dark energy is a theoretical repulsive energy that causes the acceleration to the expansion of the universe. Among the choices, the nearest answer would be D. Dark energy can also be defined as a new form of energy, that is a dynamic field that fills up space but has an effect opposite to that of normal energy.
I think it is A. but then you can also produce your own energy
[two waves] pass a point [every second]... The answer is in the question (B)
By using drift velocity of the electron, the current flow is 7.20 ampere.
We need to know about drift velocity of electrons to solve this problem. The drift velocity can be determined as
v = I / (n . A . q)
where v is drift velocity, I is current, n is atom number density, A is surface area and q is the charge.
From the question above, we know that
d = 2.097 mm
r = (0.002097 / 2) m
v = 1.54 mm/s = 0.00154 m/s
ρ = 8.92 x 10³ kg/m³
q = e = 1.6 x 10¯¹⁹C
Find the atom density
n = Na x ρ / Mr
where Na is Avogadro's number (6.022 x 10²³), Mr is the atomic weight of copper (63.5 g/mol = 0.635 kg/mol).
n = 6.022 x 10²³ x 8.92 x 10³ / 0.635
n = 8.46 x 10²⁷ /m³
Find the current flows
v = I / (n . A . q)
0.00154 = I / (8.46 x 10²⁷ . πr² . 1.6 x 10¯¹⁹)
0.00154 = I / (8.46 x 10²⁷ . π(0.002097 / 2)² . 1.6 x 10¯¹⁹)
I = 7.20 ampere
For more on drift velocity at: brainly.com/question/25700682
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The speed of the wave is mathematically given as
v=2266.66m/s
A long wave with a period of about 15 minutes will travel across the oceans at a speed of approximately v=2266.66m/s
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Speed of the wave</h3>
Question Parameters:
A long wave with a period of about 15 minutes
Generally the equation for the Wave velocity is mathematically given as
v=\lambda * frequency
Where
f=1/t
Therefore
v=\lambda * frequency
v=\lambda * 1/t
Therefore, with wavelenght of the ocean as 34km
v=34*1000*1/15
v=2266.66m/s
For more information on Speed
brainly.com/question/4931057
