An experimental setup creates a non-uniform electric field between two large
PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
An experimental setup creates a non-uniform electric field between two large, parallel metal plates that extend infinitely in the horizontal directions. The lower plate is held at 0 V and the upper plate at +200 V. Using a probe, a student traces several equipotential surfaces in the space midway between the plates. When viewed edge-on (as straight horizontal lines), the equipotential surfaces are located at the following distances d from the lower plate:
Potential (V) 0 40 80 120 160 200
Distance d (cm) 0 0.5 1.2 2.0 3.2 5.0
Assume the field and potentials vary only in the vertical direction between the plates.
(1) Determine the magnitude of the average electric field in the region between the 0 V and 40 V equipotentials.
(2) Determine the magnitude of the average electric field in the region between the 160 V and 200 V equipotentials.
(3) Rank the five regions between successive equipotentials (0–40 V, 40–80 V, 80–120 V, 120–160 V, 160–200 V) in order of electric-field strength, from greatest to least. Justify your ranking quantitatively.
(4) A +3.0 µC test charge is released from rest at the 120 V surface and allowed to move vertically. Calculate the work done by the electric field as the charge moves to the 40 V surface.