Answer
(a) $blue\lt green \lt red$
(b) $red\lt green \lt blue$
(c) $blue\lt green \lt red$
Work Step by Step
(a) We know that the when white light passes through a prism, it splits into different colors. As different colors have different wavelengths, therefore, they travel at different rates inside the prism. Thus, the required increasing order is $\lambda_{blue}\lt \lambda_{gree}\lambda_{red}$.
(b) We know that $f=\frac{c}{\lambda}$. This equation shows that frequency is inversely proportional to the wavelength and hence the highest wavelength will be the light with lowest frequency. The required increasing order is $f_{red}\lt f_{green}\lt f_{blue}$.
(c) We know that $n=\frac{\lambda P}{hc}$. This equation shows that the number of photons per second is directly proportional to the wavelength of the light. Thus, the required order is $n_{blue}\lt n_{green}\lt n_{red}$.
