The correct arrangement of colours in an increasing order of their wavelengths is :

1. Violet < Green < Red
2. Red < Green < Violet
3. Green < Violet < Red
4. Green < Red < Violet

In the spectrum of white light by a prism, the colour at the extreme end opposite to the base of a prism is —

1. violet
2. yellow
3. red
4. blue

A beam consisting of red, blue and yellow colours is incident normally on the face AB of an isosceles right-angled prism ABC as shown in the figure given below. Critical angle of glass-air interface for yellow colour is 45°.

Out of the four emergent rays P, Q, R and S, which one is for the yellow colour :

1. P
2. Q
3. R
4. S

The frequency of violet light is 7.5 x 10¹⁴ Hz. Its wavelength in nm is :

1. 7500 nm
2. 4000 nm
3. 400 nm
4. 750 nm