Assume that the noise spectral density, at any given frequency, in a current amplifier is independent of frequency. The bandwidth of measurement is changed from 1 Hz to 10 Hz. The ratio A/B of the RMS noise current before (A) and after (B) the bandwidth modification is
1
1/10
2
\(1/\sqrt {10} \)
3
\(\sqrt {10} \)
4
10