May any one give example how merkle tree is used in blockchain to verify the transaction? I confused because validation of data in ethereum is done through the proof of work where you find the nonce(hash of block + nonce) value that will less than and equal to target hash value. If I am wrong than please correct me as I am new to blockchain technology.
There is some misunderstanding. Proof of work is the mechanism of consensus. This defines the rules for mining. The Merkle tree is an architecture type of distributed database (blockchain). This defines the rules of storing data. These are two different elements of the blockchain.
Actually there is no transaction verification, you can send any transaction you want.
Common transaction lifecycle
- Mining / execution / confirmation / including in block
But after execution depends on the data and parameters, the transaction may fail or succes. Fail means that the instructions inside the transaction trows an error due to a conflict in the Merkle tree, so the data has not changed.