Answer:
40km/hr
Explanation:
Speed = Distance ÷ Time and since they both have different units we have to change one of them. Therefore if we change 30 minutes to half an hour we say 20km ÷ ¹/2
Answer:
D. As white light passes through a prism , it bends and separates into different colors
Explanation:
When light enters a prism, it experiences a phenomenon called 'refraction'.
Refraction occurs when light crosses the interface between two mediums with different optical density; when this happens, the light bends and also changes speed.
The angle at which the ray of light is refracted into the second medium depends on the optical density of the two mediums, but also on the wavelength of the light.
In particular, longer wavelengths (red color) are refracted the least, while shorter wavelengths (violet color) are refracted the most.
As a result, when white light (consisting of all the colors of visible light) enters into a prism, they different wavelengths are separated: therefore, white light separates into different colors.
So, the correct answer is
D. As white light passes through a prism , it bends and separates into different colors
