Answer:
Static electricity.
Explanation:
Electric Charge; Is the quantity of electricity held in an object
The balloon is electrically neutral, meaning it had an equal amount of positive and negative charges hence it couldn't attract the paper.
After rubbing the balloon, it gained an electric charge; and after gaining this charge it got the ability to exert a force on the pieces of paper and attract them, This is called static electricity.
Therefore, Static electricity caused the paper to stick to the balloon.
Answer:
1/4 λ film
Explanation:
Let L = total path length then L = 2 t where t is film thickness
There will be a 180 deg phase change at the air-film interface but no
phase change at the film-air interface
L = n * wavelength / 2 where n = 1, 3, 5, 7 etc
(the total path L must be an odd number of 1/2 wavelengths)
Or t = n * wavelength / 4 (the film must be an odd number
of 1/4 wavelengths thick)
1/4 λ film satisfies this condition
Note: Find the missing diagram in the attachment section.
