Multiple choice

An intrinsic semiconductor has a band gap of 1.5 eV. The wavelength of the electromagnetic radiation required to cause the material photoconducting is ________________.

  1. 3525 Å

  2. 7827 Å

  3. 8272 Å

  4. 8573 Å

  5. 9368 Å

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given, Band gap (E) = 1.5 eV = 1.5 × 1.602×10-12 erg, h = 6.627 × 10-27 erg.s, c = 3 × 1010 cm/s Now, energy of material, E = hc/λ λ = 6.627 × 10-27 × 3 × 1010/ 1.5 × 1.602×10-12 = 8.272 × 10-5 cm = 8272 Å.