Here are four statements about light:
1 In a vacuum, green light travels faster than blue light.
2 In a vacuum, the wavelength of red light is greater than the wavelength of green light.
3 In water, red light travels faster than it travels in a vacuum.
4 In water, the frequency of blue light is greater than the frequency of red light.
Which pair of statements is correct?

Answer:

3) E

1 – False. All light travel at the same speed in vacuum.

2 – True. Red light always has a larger wavelength than green light.

3 – False. All light travel faster in vacuum than in water.

4 – True. Frequency of blue light is always greater than frequency of red light.

So the answer is E (2 and 4).