A small conducting sphere is held at a fixed distance from a larger sphere which is continually charged by a generator. The surface area of the large sphere is 0.04m^2, and it discharges by sparking to the small sphere when the charge density on the large sphere reaches 0.25 C/m². charge density = charge per unit surface area If the large sphere is charged at a rate of 2 mA, calculate the time interval (in seconds) between sparks.

Answer:

27) 5 seconds

Current (I) = Charge (Q) ÷ time (t)

I = Q ÷ t

We know charge density = charge per unit surface area

Charge density (0.25) = charge ÷ unit surface area (0.04)
Charge (Q) = 0.25 x 0.04 = 0.01 C

I = Q ÷ t

I = 2mA = 0.002 A
Q = 0.01 C
t = ?

t = (Q ÷ I) = (0.01 ÷ 0.002) = 5 seconds