What is the default behaviour, if no ciphers are enabled Lets assume for example, that a server is configured to use TLS 1.0 and there are no ciphers enabled for it. 
What will be the default behaviour if a client connects to it?
Will the server use any null ciphers by default to complete the TLS handshake?
Will server use any null ciphers by default to complete the ssl
  handshake.


No. The TLS v1.0 specification explicitely states that the TLS_NULL_WITH_NULL_NULL cipher suite must not be negotiated. However, using a cipher suite that only offers authentication but no encryption is valid (and done in e.g. Windows Update). An example for such a suite is TLS_RSA_WITH_NULL_SHA.

To quote appendix A.5 of RFC2246:


  TLS_NULL_WITH_NULL_NULL is specified and is the initial state of a
  TLS connection during the first handshake on that channel, but must
  not be negotiated, as it provides no more protection than an
  unsecured connection.


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  Lets for example, a server is configured to use TLS1.0 and there is no
  ciphers enabled for it, what will be the default behaviour if a client
  connects to it.


It depends, either the server implementation will override your configuration and use the default list of accepted cipher suites, or it will refuse all incoming TLS connections because no client can offer an accepted cipher suite to the server (because it doesn't accept any).