A positive point charge (q 7.2 108 C) is surrounded by an equipotential surface A, which has a radius of rA 1.8 m. A positive te
1 answer:
<h2>Thus the radius 
is 1.2 m</h2>
Explanation:
The potential at point A due to point charge at center .
V₁ = = 7.2 x 10⁻⁸ x 9 x 10⁹ [
]
Similarly
The potential at B
V₂ = = 7.2 x 10⁻⁸ x 9 x 10⁹ [
]
The potential difference
V = V₂ - V₁ = 648 [ -
]
The work done
W = q₀ V = 4.5 x 10⁻¹¹ x 648 [ -
]
But W = 8.1 x 10⁻⁹ J
Thus equation is
8.1 x 10⁻⁹ = 4.5 x 10⁻¹¹ x 648 [ -
]
0.28 = [ -
] or
= 0.28 + 0.55 = 0.83
or = 1.2 m
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