"Diameter of a soap bubble increases when it is charged." why?
It is charged with the SAME type of charge, i.e. say you put a lot of electrons on it. Now think of what an electron would like to do to another electron (other than sucker punch it or flip its spin).
Don't believe everything you are told. Take an experimantalist's approach. Make a soap bubble. Then charge it with electricity made with a piece of plastic rubbed by woolen cloth.
I guess this is one more most-stupid-example-found-in-school-textbook-on-physics making kids hating physics and showing them that physics is a set of formulae and rules predicting world behaviour contrary to their own experience.
@ZapperZ - excercise for you:
A bubble 1cm in diameter, normal air pressure.
Charge it to 100,000V (or 1 million...)
Compute 'increase' of diameter.
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