The court and counsel for either party shall have the right to examine under oath any person who is called as a juror therein and shall have the right to ask such person or juror directly any relevant question to ascertain whether he is related to either party, or has any interest in the cause, or has expressed or formed any opinion, or is sensible of any bias or prejudice therein; and the party objecting to any juror may introduce any competent evidence in support of the objection; and if it shall appear to the court that the juror does not stand indifferent in the cause, another shall be drawn or called and placed in his stead for the trial of that case. A juror, knowing anything relative to a fact in issue, shall disclose the same in open court.