Alpha rays consist of a stream of

Find the ratio of energy for radiations having $6000 \ \mathring{A}$ and $4000 \ \mathring{A}$ wavelength.
$(h = 6.62 \times 10^{-34} \ J \ s, c = 3 \times 10^8 \ m \ s^{-1})$

Explain the properties of electromagnetic waves.

Give the formulas for wave number and time period.

The $Cs^+$ ion imparts a violet color to the flame. How is this related to the emitted radiation?

The energy of an electromagnetic radiation is $19.875 \times 10^{-13} \ erg$. What is its wave number in $cm^{-1}$? $(h = 6.625 \times 10^{-27} \ erg \ sec, c = 3 \times 10^{10} \ cm \ sec^{-1})$