Question

What is significance of dielectric strength

Answer 1

In very basic terms, the dielectric strength of a material, is the ability to the material to act as an insulator.

Were you to place a piece of cloth between two metal plates to which a variable voltage supply was attached and the cloth started conducting at 7,000 Volts, its dielectric strength would be less than that of a piece of glass that started conducting at 30,000 Volts.