There is too much information given, it's hard to understand exactly which variables are important in this problem.
Answer:
potential difference V= 300 volts
Explanation:
Given:
d= 2.0 cm = 0.02m
E = 15 kN/C = 15 × 10³ N/C
For a uniform field between two plates, the Electric Filed Intensity (E) is proportional to the potential difference (V) and inversely proportional to distance between the plates.
E= V/d
⇒ V= E×d = 15 × 10³ N/C × 0.02 m = 300 volts (∴1 Nm/C = 1 J/C= 1 volts)
