How does a walkie-talkie work and why do people still use them ?

A walkie talkie works on wires on the inside and by the battery. People still use them because they are fun and you can talk if your 6 or 10 inches away and it sounds cool!

People use them to talk faster, rather than pulling your phone out unlocking it, opening phone app, etc...you just take the walmie talkie out and push a button, and you can hear multiple people

If the heat engine is a perfect carnot cycle engine, thenefficiency = (t2-t1)/t2   where t1=temperature of cold reservoir ( ° k) = 135            t2=temperature of hot reservoir ( ° k)   = 325thereforeefficiency = (t2-t1)/t2 = (325-135)/325 = 0.5846 = 58%  note: this is the theoretical maximum efficiency of a perfect heat engine.   real-life engines do not achieve this value.