An astronomical telescope consists of two convex lenses having focal length 80 cm and 4 cm. When it is in normal adjustment, what is its:
(i) Length,
(ii) Magnifying power?
Characteristic X-rays: In continuous spectrum of radiation, a spectrum of discrete X-ray emission lines obtained that is the characteristic of target material. This is called characteristic X-rays.
A continues spectrum (X-rays) consisting of radiations of all possible wavelength with a lower wavelength unit. While a characteristic spectrum (X-rays) consisting of definite wavelength superimposed on the continuous spectrum.
(i) Define ‘unified atomic mass unit’.
(ii) Find the minimum energy which a gamma ray photon should possess so that it is capable of producing an electron — positron pair.