Why it is fine for laptop charge not having plug polarity Wh

Why it is fine for laptop charge not having plug polarity? Why it is important to have plug polarity for ovens, microwaves etc.?

Solution

1)In laptop,the end consumer is LED (light emitting diode).If you supply reverse voltage initially, it won\'t glow. However other components on the shield might get destroyed. So the fact that the LED is now glowing is not very helpful to deduce whether the shield is okay or not.that\'s why they put fine on manufacturer to not let this happen next time.

2)Iw we reverse the polarity in ovens,it would leads to burning of wires as they made up based on thier current and voltages ratings.Hence,always make sure to connect the wires with thier corresponding polarities.