How do the electrical patterns in electronics convey information

The idea is very simple.

To send information from one place to another, you have to CHANGE something that the person on the other end will notice, and you have to do it in a way that the person on the other end will understand.

If you're sending something electrical from one place to another, one way you can change it is:  You turn it on and turn it off.  The person on the other end sees: It's THERE, then it's NOT there, then it's THERE.   Maybe for some shorter times and some longer times.  

If you have a meeting with the person on the other end FIRST, and you work out patterns that you both understand, then later you can use this to send information.  Like for example ... Morse Code.

If you're using electromagnetic waves to send information, you can change something about the waves.  There are not too many of those.  The only thing you can do with waves besides turn them on and off is: ==> change their frequency, ==> change their amplitude, ==> change their phase.

Again, just like Morse Code, you have to make up patterns with the person on the other end, so that he'll understand the changes you made when you make them.

I'm not going to try to explain 'phase' changes with waves, but you're already very familiar with changing the amplitude of waves and changing the frequency of waves.

Changing their amplitude:  If you change them fast enough, and the receiver runs the waves through the right kind of electronic parts, you can use the changes to copy sounds and images.  This is how AM radio and TV pictures are sent from place to place.

Changing their frequency:  If you change them fast enough, and the receiver runs the waves through the right kind of electronic parts, you can use the changes to copy sounds and images.  This is how FM radio and TV sound are sent from place to place.

The correct answer is B) with analog and digital signals.

Electrical patterns in electronics convey information with analog and digital signals.

Electronic devices transmit information through electrical patterns called analog and digital signals. The analog signal is produced by repeatedly changing the voltage or the current in a circuit. The information is encoded in the frequency of the analog signal. In the case of the digital signal, it uses a code of "1 and 0," and result more reliable than analog signals.

The other options of the question were A) with analog and electric signals, C) with electric and thermal signals, and D) with electric and digital signal.

snell's law

refractve index = sin incidence / sin refraction