(a) Control by the Court; Purposes. The court should exercise reasonable control over the mode and order of examining witnesses and presenting evidence so as to:
(1) make those procedures effective for determining the truth;
(2) avoid wasting time; and
(3) protect witnesses from harassment or undue embarrassment.
(b) Scope of Cross-Examination. A witness may be cross-examined on any matter relevant to any issue in the case, including credibility. In the interests of justice, the judge may limit cross-examination with respect to matters not testified to on direct examination.
(c) Leading Questions. Leading questions should not be used on direct examination except as necessary to develop the witness's testimony. Ordinarily, the court should allow leading q