e way bill for job work

Yes ....eway is mandatory if value of Invoice (in your case Delivery Challan )is more than 50k & being transported via motorised conveyance

yes..it is compulsory.

if principal is unregistered then whether e way bill required to made for job work intra state if value exceeds 50k.

Yes ,. as per Rule 138 , its mandatory even if the person who is URD but moving goods more than 50k

as far as eway bill for job work in interstate supply is concerned.. it is mandatory if the value of consignment is LESS than 50k.

"Provided also that where goods are sent by a principal located in one State or
Union territory to a job worker located in any other State or Union territory, the e-way
bill shall be generated either by the principal or the job worker, if registered, irrespective
of the value of the consignment"