Semiconductors & Communication · JEE Main previous year questions

2015 2 questions

1. Q552015 · 4 Apr 2015 · Shift 1

   A red $LED$ emits light at $0.1\mathrm{watt}$ uniformly around it. The amplitude of the electric field of the light at a distance of $1\mathrm{m}$ from the diode is :

   1. A.$5.48V/m$
   2. B.$7.75V/m$
   3. C.$1.73V/m$
   4. D.$2.45V/m$
   Show answer

   Answer: D

2. Q592015 · 4 Apr 2015 · Shift 1

   A signal of $5\mathrm{kHz}$ frequency is amplitude modulated on a carrier wave of frequency $2\mathrm{MHz}$. The frequencies of the resultant signal is/are :

   1. A.$2005\mathrm{kHz}$, $2000\mathrm{kHz}$ and $1995\mathrm{kHz}$
   2. B.$2000\mathrm{kHz}$ and $1995\mathrm{kHz}$
   3. C.$2\mathrm{MHz}$ only
   4. D.$2005\mathrm{kHz}$ and $1995\mathrm{kHz}$
   Show answer

   Answer: A