A charge 50 µc has electric field strength of 360 NC-1 at a certain point. The electric field strength due to another charge 120 µc kept at the same distance apart and in the same medium is?
A
864 NC-1
B
150 NC-1
C
144 NC-1
D
18 NC-1
Verified Correct Answer: A.
Physical Principles & Numerical Solution
In general, electric field strength E = \(\frac{(F)}{q}\)
E = \(\frac{q}{4\pi\varepsilon_0d^2}\)
⇒ 360 = \(\frac{9\times10^9\times50\times10^-6}{d^2}\)
solving, we have \(d^2\) = 1250
putting \(d^2\) = 1250 into the second equation,
E = \(\frac{9\times10^9\times120\times10^-6}{1250}\)
we have E = \(864NC^-1\)
Source: Myschool Past Questions Archive (Record #13970)