Which means i key in the right seed.
Yep. Addresses should also be familiar ones that you've seen before. The same goes for transactions and balance.
You can use the getseed command to see the seed in both hex and mnemonic form. Or you can use mnemonic.py to convert any arbitrary seed from one form to another.
Electrum getseed via command line/shell:
electrum -w /path/to/wallet/file getseed
mnemonic.py: First find mnemonic.py on your file system then run this:
python /path/to/mnemonic.py word1 word2... word12