Question

Three charged particles having charges q,-2q and q are placed at points (-a,0),(0,0) and (a,0) respectively.the expression for electric potential at (0,r) is

Answer 1

Answer ⇒ 2kqa²/r(r² - a²)

Explanation ⇒ At a point P(r,0), Potential will be due to three charges namely q, -2q , and q.

Now,

Potential at Point P due to -2q = k(-2q)/r = -2kq/r

Potential at point p Due to q = kq/(r-a) + kq/(r + a)

= kq[r + a + r - a]/(r² - a²)

= 2kqr/(r² - a²)

Net Potential = Potential at Point P due to -2q + Potential at Point P due to q

∴ Net Potential = -2kq/r + 2kqr/(r² - a²)

= 2kq[-1/r + r/(r² - a²)]

= 2kq[-r² + a² + r²]/r(r² - a²)

= 2kqa²/r(r² - a²)

Hence, the net potential at point P is 2kqa²/r(r² - a²).

Answer 2

Explanation:

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