Answer:
Q = -52.56 nC
Explanation:
The electric field outside a spherical shell is given by
[tex]E = \frac{k*Q}{r^{2} }[/tex]
where:
Q is the net charge
r is the radius of the spherical shell and E is the electric field magnitude.
Given:
r = 0.725 m
since the field points radially toward the center of the sphere, E = -899 N/C.
k is a constant with a value = 8.99 x 109 Nm²/C².
∴[tex]-899 = \frac{8.99*10^{9} *Q}{0.725^{2} }[/tex]
[tex]Q = \frac{-899*0.725^{2} }{8.99*10^{9} }=-5.256*10^{-8}[/tex]
Q = -52.56 nC