OCR MEI
Further Pure Core
2023
June
Q9
6 marks
Standard +0.3
9 In an electrical circuit, the alternating current \(I\) amps is given by \(\mathbf { I } =\) asinnt, where \(t\) is the time in seconds and \(a\) and \(n\) are positive constants. The RMS value of the current, in amps, is defined to be the square root of the mean value of \(I ^ { 2 }\) over one complete period of \(\frac { 2 \pi } { n }\) seconds.
Show that the RMS value of the current is \(\frac { a } { \sqrt { 2 } }\) amps.