Chemistry - Atomic Structure Question with Solution | TestHub

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency ' $\mathrm{A}$ ' $\times 10^{12}$ hertz and that has a radiant intensity in that direction of $\frac{1}{{}^{\prime }{\mathrm{B}}^{\prime }}$ watt per steradian. 'A' and 'B' are respectively