Red light always has a lower frequency than blue light.
(a) In a vacuum, these two colors are known to travel at the same speed. How do their wavelengths compare in vacuum? Choose one answer only.
wavelength of blue > wavelength of red
wavelength of red = wavelength of blue
wavelength of red > wavelength of blue
(b) In a certain type of glass, these colors are known to have the same wavelength. How do their wave speeds compare in this glass? Choose one answer only.
average speed of red > average speed of blue
average speed of blue > average speed of red
average speed of red = average speed of blue
Lower frequency ---> longer wavelength
because
T = 1/f = distance/speed
then for part B
we know the frequency of red is lower.
The frequency and period DO NOT CHANGE (there is no place to store extra waves)
Therefore if the wavelength of red gets shorter it had to cover less ground in a period. It went slower.
(a) In a vacuum, light travels at the same speed regardless of its color. The speed of light in a vacuum is approximately 3 x 10^8 meters per second. Therefore, the wavelengths of red and blue light in vacuum are directly related to their frequencies according to the equation c = λν, where c is the speed of light, λ is the wavelength, and ν is the frequency. Since the speed of light is the same for both red and blue light, their wavelengths are inversely proportional to their frequencies. So, the correct answer is: wavelength of red = wavelength of blue.
(b) In a certain type of glass, the speed of light is different for different colors. This is due to the phenomenon of dispersion, where different wavelengths of light are refracted at different angles. In general, the refractive index of a material depends on the wavelength of light, which affects the speed of light in that medium. In the case of the given glass, since the colors red and blue have the same wavelength, their wave speeds will be the same. Therefore, the correct answer is: average speed of red = average speed of blue.