Answer:
The wavelength in vacuum is equal to 428.8 nm.
Explanation:
Given that,
The wavelength of light, 
The refractive index of glass, n = 1.51
We need to find the wavelength in vacuum. The relation between wavelength and refractive index is given by :

So, the wavelength in vacuum is equal to 428.8 nm.
Answer:
False, Sunspots appear dark (in visible light) due to their low temperature(cooler) than rest of the sun
Explanation:
Sunspots appear dark because they are much cooler( have low temperature than the rest of the surface contained by Sun. As they appear dark, but still they have very temperature that's why so hot. Sunspots have temperatures ranges 3,500 Celsius (3773 kelvin) and the surrounding surface of the sun has a temperature much higher of about 5,500 Celsius(5773 Kelvin). Even if we see a sunspot alone in space, it will glow so brightly.
Learn more about sunspots :
brainly.com/question/27774496
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Answer:
0 (there is no speed)
Explanation:
If an object is at rest, it is not moving, and it doesn't have a speed, so the speed is zero.
1. neutral particles (neutrons) are in the nucleus
2. nucleus is in the nucleus
3. electron cloud is in the electron cloud
4. positively charged particles (protons) are in the nucleus
5. negatively charged particles (electrons) are in the electron cloud