Question

explain energy units for expressing nuclear energy​

Answer 1

Joule is the unit used to measure all forms of energy. However in some cases nuclear energy is measured in electron volts (ev). Energy of subatomic particles and other emissions produced in a nuclear reaction is very small compared to one joule. So a much smaller unit ie.

Answer 2

$hey \: your \: answer$

The standard unit of energy in SI is always the Joule using mks ...and the erg in cgs.

That being said, a unit of energy often used in nuclear physics and engineering when discussing nuclear reactions is the MeV or Mega Electron Volt which is 1,000,000 times the electrostatic energy that a single electron has when elevated to a potential of one volt.

$\blue{hope\:it\:helps!!!}$