Find the correct value of new resistance below:
 
A copper wire has diameter \(0.5\ mm\) and resistivity of \(2 \times\ 10^{–8}\ \Omega\ m\). What will be the length of this wire to make its resistance 29 Ω? How much does the resistance change if the diameter is doubled?
 
[Take the value of \(\pi\) as \(3.14\)]
 
The length of the wire, \(l\ =\) \(m\)
 
If the diameter of the wire is doubled, the new diameter is \(m\)
 
The new resistance, \(R^{'}\)  \(=\)  Ω
 
The new resistance, \(R'\) by \(\Omega\)
 
[Note: Enter the answer upto two decimal places.]