Download App

STD 12 - 14. Semicondutor electronics — NEET STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceNEETSTD 12 - 14. Semicondutor electronics4 Marks
MCQ
A light emitting diode $(LED)$ is fabricated using GaAs semiconducting material whose band gap is $1.42 \mathrm{eV}$. The wavelength of light emitted from the $LED$ is:
  • A
    $650 \mathrm{~nm}$
  • B
    $1243 \mathrm{~nm}$
  • ✓
    $875 \mathrm{~nm}$
  • D
    $1400 \mathrm{~nm}$
✓

Answer

Correct option: C.
$875 \mathrm{~nm}$
c
$\lambda=\frac{1240}{1.42}=875 \mathrm{~nm}$ $(Approx)$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

NEET STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

Two identical short bar magnets, each having magnetic moment $M,$ are placed a distance of $2d $ apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is
→
A $50\, W$ bulb is in series with a room heater and the combination is connected across the mains. To get max. heater output the $50\, W$ bulb should be replaced by ......$W$
→
In a radioactive sample there are $1.414 \times 10^6$ active nuclei. If they reduce to $10^6$  within $10\, minute$ then the half life of this sample will be ....... $min$
→
The effective capacity between $A$ and $B$ in the figure given is
→
A constant force $F$ is applied in horizontal direction as shown in figure. Contact force between $M$ and $m$ is $N$ and between $m$ and $M'$ is $N'$ then
→
The displacement y of a particle in a medium can be expressed as: $y = {10^{ - 6}}\sin (100t + 20x + \pi /4)m,$ where $t$ is in second and $x$ in meter. The speed of wave is ... $m/s$
→
If three particles each of mass $M$ are placed at the corners of an equilateral triangle of side $a$ , the potential energy of the system and the work done if the side of the triangle is changed from $a$ to $2a$ , are
→
A glass wind screen whose inclination with the vertical can be changed is mounted on a car. The car moves horizontally with a speed of $2\,\,m/s$. At what angle $\alpha$ with the vertical should the wind screen be placed so that the rain drops falling vertically downwards with velocity $6\,\, m/s$ strike the wind screen perpendicularly.
→
A student determined Young's Modulus of elasticity using the formula $Y=\frac{M g L^{3}}{4 b d^{3} \delta} .$ The value of $g$ is taken to be $9.8 \,{m} / {s}^{2}$, without any significant error, his observation are as following.

Physical Quantity Least count of the Equipment used for measurement Observed value
Mass $({M})$ $1\; {g}$ $2\; {kg}$
Length of bar $(L)$ $1\; {mm}$ $1 \;{m}$
Breadth of bar $(b)$ $0.1\; {mm}$ $4\; {cm}$
Thickness of bar $(d)$ $0.01\; {mm}$ $0.4 \;{cm}$
Depression $(\delta)$ $0.01\; {mm}$ $5 \;{mm}$

Then the fractional error in the measurement of ${Y}$ is

→
Force of attraction between the plates of a parallel plate capacitor is
→