Hurry !
an electroscope is a device that detects charge on objects that touch it or are brought near it. john rubs a piece of cotton fabric on a plastic rod and then touches the rod to the electroscope. what methods of charging does john use?
a. john charges the rod through induction, then charges the electroscope through friction.
b. john charges the rod through conduction, then charges the electroscope through induction.
c. john charges the rod through friction, then charges the electroscope through induction.
d. john charges the rod through friction, then charges the electroscope through conduction.

D. John charges the rod through friction, then charges the electroscope through conduction.

Explanation:

There are three ways by which charge can be transferred:

1. Conduction- when charged object is brought in contact with an uncharged object, electrons are transferred and the uncharged object becomes charged.

2. Induction- when a charged object is brought near an uncharged object, charge is induced.

3. Friction- charging by friction occurs when two bodies having different electro-negativity are rubbed, one loses electrons to another and both become charged.

In the given situation, john initially rubs a piece of cotton fabric on a plastic rod. Both become charged by friction.

Then, John touches the charged rod to the electroscope, the transfer of charge takes place through conduction.

It's D!!!

Explanation:

d. air pressure decreases as altitude increases.