What is a Light Emitting Diode? Draw its circuit symbol.
A Light Emitting Diode (LED) is a semiconductor device that emits light when current flows through it in the forward direction. It operates based on the principle of electroluminescence, where electrons recombine with holes, releasing energy in the form of photons (light). The circuit symbol for an LED is:
Derive an expression for energy stored in a charged capacitor. A spherical metal ball of radius 15 cm carries a charge of 2μC. Calculate the electric field at a distance of 20 cm from the center of the sphere.
Draw a neat labelled diagram of Ferry's perfectly black body. Compare the rms speed of hydrogen molecules at 227°C with rms speed of oxygen molecules at 127°C. Given that molecular masses of hydrogen and oxygen are 2 and 32, respectively.
Distinguish between an ammeter and a voltmeter. (Two points each).
The displacement of a particle performing simple harmonic motion is \( \frac{1}{3} \) of its amplitude. What fraction of total energy is its kinetic energy?
Using the geometry of the double slit experiment, derive the expression for the fringe width of interference bands.
An alternating voltage is given by \( e = 8 \sin(628.4 t) \).
Find:
(i) Peak value of e.m.f.
(ii) Frequency of e.m.f.
(iii) Instantaneous value of e.m.f. at time \( t = 10 \, {ms} \)