A laboratory has parallel-plate capacitors of fixed plate area and fixed separation

PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

A laboratory has parallel-plate capacitors of fixed plate area A=250 cm2A = 250\,\text{cm}^2 and fixed separation d=3 mmd = 3\,\text{mm}. The air-filled capacitance is found to be too small for a particular experiment, which requires at least a 60%60\% increase over the air value without changing AA or dd. The store room offers four dielectric materials with relative permittivities as follows: Material P: κ=2.1\kappa = 2.1 Material Q: κ=3.4\kappa = 3.4 Material R: κ=4.5\kappa = 4.5 Material S: κ=5.2\kappa = 5.2 Only one slab, completely filling the space between the plates, can be used. (i) Determine which of the four materials can individually satisfy the experimental requirement. (ii) For the material(s) identified in part (i), calculate the new capacitance value. (iii) Explain, with quantitative support, why the other materials do not meet the requirement.

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