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 maximum speed of a vehicle moving along a horizontal circular track.
If the mean and variance of a binomial distribution are \( 18 \) and \( 12 \) respectively, then the value of \( n \) is __________.