Question

The large horizontal metal plates are separated by 4 mm. The lower plate is at a potential Vg =−6 V. What potential should be applied to the upper plate to create an electric field of strength 4000 V/m upward in space between plates?

A. V=−2 V
B. V=−4 V
C. V=−8 V
D. V=−12 V

Answer 1

To create an electric field of strength 4000 V/m upward in the space between the plates, a potential of -10 V should be applied to the upper plate.

Step-by-step explanation:

To create an electric field of strength 4000 V/m upward in the space between the plates, we need to find the potential applied to the upper plate.

The electric field strength between the plates is given by the formula E = ∆V / d, where E is the electric field strength, ∆V is the potential difference, and d is the separation between the plates. Rearranging the formula to solve for ∆V, we have ∆V = E * d. Plugging in the given values, ∆V = 4000 V/m * 0.004 m = 16 V.

Since the upper plate is at a potential Vg = -6 V, the potential applied to the upper plate is the sum of Vg and ∆V: V = Vg + ∆V = -6 V + 16 V = 10 V. However, the potential should be applied in the opposite direction, so the correct potential is V = -10 V.

Therefore, the potential that should be applied to the upper plate to create an electric field of strength 4000 V/m upward is V = -10 V.