Part – 1 (Every Physical object…) was posted on February 7, 2019

EVM is a microprocessor based system, like most of the electronic instruments today dedicated to act as a voting machine.
A microprocessor is a miniaturized computer system, it has the CPU, the control unit and input and output unit, can carry on various arithmetic and logical operation compared to modes sophisticated instrumentation systems, EVM is a rather simple system.

Hacking EVM is so costly and complex that one can state simply that they cannot be hacked.
A large scale hacking of EVM machines need a dedicated chip design which will not only really costly but also need Complex technology which is not available easily.
While it is naive to make claims such as that our currency cannot be faked or our examination system is so secure that no one can pass it using unfair means or that EVM’s cannot be hacked. Only those situations are impossible that violates laws of thermodynamics. For example:- no one can make a machine showing perpetual motion because it violates second law of thermodynamics. Here when we claim that our examination system or currency is so secure that no one can hack it. What it simply implies is that the cost, efforts, number of persons that need to be ganged up in order to do such an illegal task is so enormous that it will serve no useful purpose. For example:- If to hack a single EVM machine it cost you about some millions of rupees and hiring of experts from top US universities and year of technical work. Obviously for all practical purposes we can claim that the machine cannot be hacked. This is like saying that if to make a fake currency note of 500 rupees with all the security features as that of real one, if the cost comes out to be rupees 1000 per fake note, obviously no sensible gang will do it. 
Hacking can only be done using antenna connected to inside circuitry of EVM and this antenna cannot be reduced in size beyond a limit due to Basic Physics limitations.
For those interested in more technical details the article written by Dhiraj Sinha from MIT is recommended.

An Expert Explains: Why hacking EVMs are tough and defy science