We know that \(v = fλ\)
Putting the values,
\(\frac{3 \times 10^8}{\sqrt{6.25}} = f \times 20\times 10^{-3}\)
\(⇒ f = 6 \times 10^9 Hz\)
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).

Method used for separation of mixture of products (B and C) obtained in the following reaction is: 
The main properties of waves are as follows –