Question

Consider a disk of radius 4.9 cm with a uni- formly distributed charge of +5.6 (C. Compute the magnitude of the electric field at a point on the axis and 3 mm from the center. The value of the Coulomb constant is 8.98774 x 10 N m2/C2

Answer 1

Answer:

$E=1.27\times 10^{12}\ N/C$

Explanation:

Given that,

Radius of the disk, r = 4.9 cm = 0.049 m

Charge, q = +5.6 C

We need to find the the electric field at a point on the axis and 3 mm from the center, x = 0.003 m

At a point on the axis of a ring, the electric field is given by :

$E=\dfrac{kqx}{(x^2+r^2)^{3/2}}$

$E=\dfrac{9\times 10^9\times 5.6\times 0.003}{(0.003^2+0.049^2)^{3/2}}$

$E=1.27\times 10^{12}\ N/C$

So, the electric field at a point on the axis is $1.27\times 10^{12}\ N/C$.  Hence, this is the required solution.