LokeshH says:
name = Request.Form[
"n_fullname"
];
emailid = Request.Form[
"n_email"
];
You cant get the values directly like above in master page because when the page is loaded it is rendered in HTML and then the id and name property is assigned with something like below
ctl00$ContentPlaceHolder1$fullname
ctl00$ContentPlaceHolder1$email
so you need to access the values in code like below identifying it with the UniqueID like below
Request.Form[fullname.UniqueID]
Request.Form[email.UniqueID]