Which microscope is used for nanotechnology?

Light of wavelength $2475 \, Å$ is incident on barium. Photoelectrons emitted describe a circle of radius $100 \, cm$ in a magnetic field of flux density $\frac{1}{\sqrt{17}} \times 10^{-5} \, T$. The work function of the barium is .............. $eV$ (Given $\frac{e}{m} = 1.7 \times 10^{11} \, C/kg$)

The dual nature of radiation is demonstrated by:

The spectrum of an oil flame is an example of:

The anode voltage of a photocell is kept constant. The wavelength of the incident light on the cathode is changed gradually. Then,the photoelectric current $I$ of the photocell varies according to which of the following graphs?

Dual nature of light is exhibited by