Electric field inside a Superconductor

[dRic2]

TL;DR

Is electric field inside a superconductor always zero ?

I was reading chapter 3 of this book https://blackwells.co.uk/bookshop/product/Superconductivity-by-James-Arnett/9780198507567, which is a brief introduction to superconductivity. It is stated that inside a superconductor the Electric filed is always zero. This is deduced from the equation $\mathbf j = \sigma \mathbf E$ and taking as an experimental evidence that $\sigma \rightarrow \infty$ for a superconductor (page 51).

What if I apply an external time-varying electric field ? Is $\mathbf E$ still zero ? It would be like the electrons instantaneously move to adapt to the new field... Is is possible ?

 

[hutchphd]

Not exactly, but way close enough for most things. Speed of light.
Never forget Admiral Grace Hopper's admonition the a foot corresponds to a nanosecond so unless your conductor is large or frequency high no worries

 

[dRic2]

Thanks, just wanted to be sure because the author refers to this property various times in the next pages to prove stuff.