The following sketch represents a specific wave of light. What will be the color of the light represented by this wave?

Find the energy of radiation having $7000 \ \mathring{A}$ and $400 \ nm$ wavelength. $\left( h = 6.62 \times 10^{-34} \ J \ s, c = 3 \times 10^8 \ m/s \right)$

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

An atom emits energy equal to $4 \times 10^{-12} \, erg$. To which part of the electromagnetic spectrum does it belong?

Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength $6800 \, \mathring{A}$. Calculate threshold frequency $(v_{0})$ and work function $(W_{0})$ of the metal.

Which of the following series of emission spectral lines for hydrogen is observed in the visible region?