When I validate my script through 'Check a user path', the entire script is getting executed in around 30 Sec but when I am running my script for 1Vuser and 1Iteration, It is taking around 16 minutes.
What can be the reason as I think response time should be same for 1vuser for both the cases.
What you describe is not the response time but the user journey duration. When validating your user path the think times are not executed which is the default behavior. It can be enabled in the checkvu panel under the advanced settings.
At runtime they are executed. You can configure the think time at page level or at the user path level to override all of them.
For more details you can look at the NeoLoad documentation here
