Electrostatics Question 720
Question: A thin glassrod is bent into a semicircle of radius r. A charge +Q is uniformly distributed along the upper half, and a charge -Q is uniformly distributed along the lower half, as shown in fig. The electric field E at P, the center of the semicircle, is
Options:
A)
B)
C)
D)
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Take PO as the x-axis and PA as the y-axis, Consider two elements EF and Ef of width
The magnitude of the fields at P due to either element is
esolving the fields, we find that the components along PO sum up to zero, and hence the resultant field is along PB. Therefore, field at P due to pair of elements is
