The gold leaf electroscope is charged so that it leaves somewhat diverge. What will happen if X – rays are incident on the electroscope?
(A) the divergence will decrease
(B) the divergence of leaves will remain unchanged
(C) the gold leaves will melt
(D) the divergence will increase

Hint: Gold leaf electroscope has two gold leaves suspended from a metal (brass) stem in a glass jar which is vacuumed and connected with a metal cap. The glass is grounded with the help of a metal foil to make it uncharged. X – rays are radiation which ionizes and when air is passed, they create ions.

Complete step by step solution:
First, we should know about the gold leaf electroscope. So, the gold leaf electroscope has two gold leaves suspended from the metal stem in the jar which is vacuumed. It is connected via a metal cap. For making it uncharged the glass is grounded with the help of metal foil. The gold leaf electroscope can detect charge. When the leaves diverge, the body is charged and the body remains unchanged when there is no effect on leaves.
X – rays are the ionizing radiation. When the gold leaf electroscope is exposed to X – rays they can lose their charge because when X – rays are passed from air they create ions. So, the newly created ions attract the leaves which are charged. Therefore, the divergence will decrease.

Hence, the correct option is (A).

Note: At first, the electroscope is charged by the body which is known, so let’s say it is positively charged then that body is removed. Then, the body is made to make contact with the metal cap and is brought under the test. Thus, when the leaves diverge further, the body has the same charge and when they come close to each other, they have opposite charges.