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Two point charges +q and −q are placed at positions (−a, 0) and (+a, 0). The electric field at the origin (0, 0) is:
AZero
BOf magnitude 2kq/a², pointing from +q toward −q (i.e., along the −x direction in this setup, from +q at −a to −q at +a)
COf magnitude kq/(2a)², perpendicular to the dipole axis
DOf magnitude kq/a², along the +x direction
Answer & Solution
Correct answer: B. Of magnitude 2kq/a², pointing from +q toward −q (i.e., along the −x direction in this setup, from +q at −a to −q at +a)
At origin: field from +q (at x = −a) points to +x (away from +q); field from −q (at x = +a) points to +x (toward −q). Both fields point the **same direction** (+x), magnitudes equal: E_each = kq/a². **Total E = 2kq/a² toward −q**, i.e., along +x.
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