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. (1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. (2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (3) (A) is true but (R) is false
4. (4) Both (A) and (R) are false
View Answer
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).
Assertion (A): Excess charge on a conductor resides entirely on the outer surface.
Reason (R): Like charges repel each other.
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
View Answer
Assertion (A) is true. Excess charges on a conductor spread out on the outer surface due to mutual repulsion. Reason (R) is also true, as like charges repel. (R) correctly explains (A).