[{"student_id":1,"marksCard_list":[{semester:"sem-1",marks:[1,2,3]},{semester:"sem-2",marks:[1,2,3,4]}],"result":"pass"},{"student_id":2,"marksCard_list":[{semester:"sem-1",marks:[1,2,3,4]}],"result":"pass"}]

db.collection.aggregate({$match:{"student_id":1}},{$unwind:"$marksCard_list"},{$match:{"marksCard_list.semester":"sem-1"},},{"$project":{"marksCard_list.marks":1}})