Mention the colours which have the least and the most wavelength in visible light.

(N/A) In the visible spectrum of light,the wavelength range is approximately $380 \ nm$ to $750 \ nm$.
According to the $VIBGYOR$ sequence:
$1$. The colour with the least wavelength is Violet,which is approximately $380 \ nm$ to $450 \ nm$.
$2$. The colour with the most wavelength is Red,which is approximately $620 \ nm$ to $750 \ nm$.