Question bank/JEE Main/Physics

JEE MainPhysicsModerateCapacitance

A fiber sheet with relative permittivity 5 is inserted between
two parallel metal plates 0.25 cm apart. A potential difference of 2500

v is applied between the plates. If dielectric strength of air is

3×106v/m3 \times 10^{6}v/m than

Show answer and solution
As V=V1+V2V = V_{1} + V_{2}
2500=0.0002E1+0.0023E22500 = 0.0002E_{1} + 0.0023E_{2}
2E1+23E2=25×1062E_{1} + 23E_{2} = 25 \times 10^{6}
Also
E1=5E2E_{1} = 5E_{2}
Solving
E2=0757×108V/mE_{2} = 0757 \times 10^{8}V/m
As
E1>3.6×106E_{1} > 3.6 \times 10^{6} Hence Air will breakdown

Source: Grass-G / P-17 Physics paper 26 Nov Second.docx

Need a video for this idea?

Scan any doubt from your notes and get a whiteboard explanation.