Answer:
The speed of this light and wavelength in a liquid are 
and 442 nm.
Explanation:
Given that,
Wavelength = 650 nm
Index refraction = 1.47
(a). We need to calculate the speed
Using formula of speed
Where, n = refraction index
c = speed of light in vacuum
v = speed of light in medium
Put the value into the formula
(b). We need to calculate the wavelength
Using formula of wavelength
Where, 
= wavelength in vacuum
= wavelength in medium
Put the value into the formula
Hence, The speed of this light and wavelength in a liquid are and 442 nm.
You should trust the primary source more.
This is because the primary source is make its conclusion from direct observation, while the secondary source is possibly making reference to another secondary source or to another primary.
The primary source should be trusted more because it is from direct observation.
At the given erro in angle, the error in the measurement of sin 90 degrees would be 0.001.
<h3>
Percentage error</h3>
The percentage error of any measurement is obtained from the ratio of the error to the actual measurement.
The error of sin 90 degrees is calculated as follows;
sin 90 = 1
error in measurement = sin(90 - 0.5)
error in measurement = sin(89.5) = 0.999
<h3>Error in sin 90 degrees</h3>
Error in sin 90 degrees = 1 - 0.999
Error in sin 90 degrees = 0.001
Thus, at the given erro in angle, the error in sin 90 degrees would be 0.001.
Learn more about error in measurement here: brainly.com/question/26668346
