Which has higher wavelength 380nm or 780nm?

380nm

Can you explain why? I don't understand how 780 is higher than 380 in number but lower in wavelength. This is like you tell me that somebody that is 7feet tall but shorter than somebody that is 3feet tall.

Its confusing I know, Lets start out with the nm what does that mean?

10^-9 of a meter

If you were to look at a diagram of wavelength, you would see that the waves get closer together the closer to zero you go, the more energy each wave has.

ohh, this is about energy not length. If it length then 780 is higher but wave then it is 380.I think I got it

Good!