The cause of Fraunhoffer lines is

The origin of the Fraunhoffer lines was explained by

Who explained the Fraunhoffer line in the spectrum of solar radiations?

During total solar eclipse Fraunhoffer's lines appear bright because -

In differation angle of first minima of Fraunhoffer diffraction is (pi)/(6) width of slit d =......

Fraunhoffer Diffraction

What is diffraction of light? How does it differ from interference? What are fraunhoffer and Fresnel diffractions?

What will be the angle of diffraction for the first minimum due to Fraunhoffer diffraction with sources of light of wavelength 550 nm and slit of width 0.55 mm ?