The band gap of semiconductor used for fabrication of visible LED'S must at least be `1.8 eV`.Explain

Explain why elemental semiconductor cannot be used to make visible LEDs

the band gap in germanium and silicon in eV are

Figure shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell.The balance point of the cell in open circuit is 76.3 cm.When a resistor of 9.5 Omega is,used in the external circuit of the cell,the balance point shifts to 64.8 cm length of the potentiometer wire. Determine the internal resistance of the cell.

Explain electrical property of: Semiconductors, on the basis of band theory.

Three photo diods D_1 , D_2 and D_3 are made of semiconductors having band gaps of 2.5 eV, 2eV and 3eV, respectively. Which ones will able to detect light of wave length 6000 overset @(A) ?

A p -n photodiode is fabricated from a semiconductor with band gap of 2.8 eV . Can it detect a wavelength of 6000nm ?

if the band gap between valence band and conduction band in a matereial is 5.0 eV , then the material is

Answer the following question: Water must not be used to extingusih fire caused by short circuit. Explain why.