Properties of Semiconductors: Practice Problem & Solution

GaAs (with a band gap = 1.5 eV) as an LED can emit :

Blue light

Green light

Infrared rays

Ultraviolet rays

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Properties of Semiconductors. Understanding the underlying formula is key to arriving at the correct answer below:

GaAs (Gallium Arsenide) with a band gap of 1.5 eV can emit light in the infrared region of the electromagnetic spectrum.

The energy of a photon emitted by an LED is related to its wavelength by the equation:

$E = \frac{hc}{\lambda}$

Solving we get

$λ= 826 nm which lies in infrared region.Leave a Reply Cancel reply Your email address will not be published. Required fields are marked * Comment * Name * Email * Website Save my name, email, and website in this browser for the next time I comment. Δ document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() );Similar Practice Questions Explore conceptually related problems to test your knowledge. 1. A conducting wire of Copper and Germanium are cooled from room temperature to temperature 80K, then their resistance will : Check solution » 2. Assertion (A): Width of depletion region is reduced in forward bias.

Reason (R): In n-type semiconductor majority charge carriers are free electrons while in p-type they are holes. Check solution » 3. Intrinsic germanium and silicon at absolute zero temperature behave like : Check solution » 4. Assertion (A): P-type semiconductor has high density of holes in valence band while N-type semiconductor has high density of electrons in conduction band.

Reason (R): In N-type semiconductor, as the density of donor atoms (N_D) is increased, the fermi energy level shifts towards the valence band. Check solution » 5. The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $6200 A^0$, is incident on it. The band gap in (eV) for the semiconductor is Check solution »© 2026 Rankers Physics. All Rights Reserved.{"prefetch":[{"source":"document","where":{"and":[{"href_matches":"/*"},{"not":{"href_matches":["/wp-*.php","/wp-admin/*","/wp-content/uploads/*","/wp-content/*","/wp-content/plugins/*","/wp-content/themes/Rankers%20Physics/*","/*\\?(.+)"]}},{"not":{"selector_matches":"a[rel~=\"nofollow\"]"}},{"not":{"selector_matches":".no-prefetch, .no-prefetch a"}}]},"eagerness":"conservative"}]}{"baseUrl":"https://s.w.org/images/core/emoji/17.0.2/72x72/","ext":".png","svgUrl":"https://s.w.org/images/core/emoji/17.0.2/svg/","svgExt":".svg","source":{"concatemoji":"https://rankersphysics.com/wp-includes/js/wp-emoji-release.min.js?ver=7.1.4"}}/*! This file is auto-generated */
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