problem based ontransmission line

a transmission line of length 50cm with L=10μH/m,c=40pf/m is operated at 30Mhz.what is its electrical length?

it's a little trouble to calculate it.
You can divide the length into 10 segments, and setup models, then calculate GD(group delay) or lamda, then you know electrical length.

This page helps to answer your question:

http://www.microwaves101.com/encyclo...wavenumber.cfm

I divided 50cm into 10 segments, each is 5 cm. So use 11 shunting 2pF caps and 10 series 0.5uH inductors.
The system group delay is 2.278ns, so the electric length is 0.068 lamda.