If a star’s light is shifted to the red part of the light spectrum, that means
that the light waves we see when we look at that star are longer than
they SHOULD be ... longer than they were when they left the star.
Note:
The wavelengths are NOT "getting longer" while we sit there and look
at them. That doesn't happen. They ARE longer than they should be.
Right now, the only way we KNOW OF that can increase the wavelength
of light is if the source of the light is moving AWAY from us, and so we
mark that star down in our notebook, and next to it we write "This star is
moving away from us.". This is kind of what choice-C is trying to say.
The thing about this whole story that should blow our minds is this:
-- We observe a star or a galaxy.
-- The light we observe has wavelengths longer than they should be.
-- We say that the star or galaxy is moving away from us.
Now, my question to you is:
HOW do we know what the wavelengths SHOULD be ? ?
We only know what we see. How do we know what the
wavelength was when the light left the star or galaxy ?
Explanation:
Power = current × voltage
P = IV
2 W = I (20 V)
I = 0.1 A
Answer:
The speed of the stone is
v = 7.45 m/s
Explanation:
Length, L=0.551m
maximum tension in the spring = 9.6%
So let speed of stone be
Tv = TH + 9.6/ 100 * TH
Tv - m*g = m*v^2/L
TH = m*v^2 / L
Factor mass to cancel in the equation
Solve to v
v^2= L*g*100 / 9.6
Replacing numeric:
v^2=0.551m*9.8m/s^2*100 / 9.6
v = sqrt( 56.24 m^2/s^2)
v = 7.45 m/s
Herz is a measurement for how many cycles of the wave occur per second, which in this case is 261. the period is the time it takes to complete 1 cycle, so if 261 cycles occur per second, one cycle occurs every 1/261 seconds
Answer:
I = 0.25 [amp]
Explanation:
To solve this problem we must use ohm's law which tells us that the voltage is equal to the product of the current by the resistance.
V = I*R
where:
V = voltage [Volt]
I = amperage or current [amp]
R = resistance [ohm]
Since all resistors are connected in series, the total resistance will be equal to the arithmetic sum of all resistors.
Rt = 2 + 8 + 14
Rt = 24 [ohm]
Now clearing I for amperage
I = V/Rt
I = 6/24
I = 0.25 [amp]