get name of table in repository design pattern

I am working in project using generic repository design pattern and i need to get the name of entity(name of table) that sent to the following Add function

 public class Repository<TEntity> : IRepository<TEntity> where TEntity:class
 {
   public TEntity Add(TEntity entity)
    {      
        validate("nameoftable");                 
        TEntity result= _set.Add(entity);
        return result;            
  }

 private validate(string entity-name)
 {
 if (entity-name == "students")
   {
    ////do some work
   }
 }

i want to get the entity table to use it for some validation before save