X-ray on Gold Leaf Electroscope – Rankers Physics

Properties of Charges: Practice Problem & Solution

Assertion (A): If X-ray is allowed to fall on uncharged gold leaf in evacuated glass chamber of electroscope, leaves will diverge. Reason (R): Uncharged gold leaves will get charged positively when x-ray falls on it.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Properties of Charges. Understanding the underlying formula is key to arriving at the correct answer below:

X-rays have sufficient energy to eject electrons from the gold leaves (photoelectric effect), leaving them positively charged. The like positive charges on the leaves cause them to repel and diverge. Thus, (R) correctly explains (A).

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