I’m pretty sure it’s, B. An Electric Motor. I apologize in advance if it’s incorrect.
Answer:
1) The matter absorbs or reflects the light
2) Lens
3) <u><em>Concave</em></u>- curves inwards. Diverges light
b.<u><em>Convex</em></u>- curves outward. Converges light
4) The image is real if the distance of the object from the lens is greater than the focal length and virtual if it is less than the focal length
5) Lens and, for convex lenses, on the distance between the lens and the object.
6) Index of refraction?
Explanation:
I hope this helped you, sorry if anything is wrong
<span>Days and nights are equal in length everywhere.(gradpoint)</span>
To solve this problem it is necessary to use the concepts related to Snell's law.
Snell's law establishes that reflection is subject to

Where,
Angle between the normal surface at the point of contact
n = Indices of refraction for corresponding media
The total internal reflection would then be given by





Therefore the
would be equal to



Therefore the largest value of the angle α is 30.27°