Delete Child Records When Parent Got Deleted in Lookup Relationship

For this We have taken Two object Teacher(Parent Object) and Employee(Chile Object)

Teacher Structure (PARENT):-

Employee Structure(CHILD) :-

Trigger on Parent Object(Teacher) :-

trigger onParentObjectDelete on Teacher__c (before delete){    
    list<ID> Teacherlist = new list<ID> ();
    
    if(Trigger.isbefore && Trigger.isDelete)
    {
        For(Teacher__c T:Trigger.old)
        {
            Teacherlist.add(T.ID);    
        }
    }
    
    List<Employee__c> EmpList= [Select ID, Teacher_lookup__c from Employee__c 

                                            where Teacher_lookup__c IN :Teacherlist ];           
    delete EmpList;    
}