Question
A charged gold leaf electroscope has its leaves apart by certain amount having enclosed air. When the electroscope is subjected to $X$-rays, then the leaves

Answer

(c)

A charged gold leaf electroscope has its leaves apart by certain amount having enclosed air. When an electroscope is subjected to $x$-rays, then the $x$-ray will ionize the air around the leaves into positive and negative charges. Hence, the charge created in the air and opposite to the gold leaf will move towards it. Thus, the opposite charges neutralize the charge on the leaf, causing the leaf to collapse.

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