(a) Control by judge. The judge shall exercise reasonable control
over the mode and order of interrogating witnesses and presenting
evidence so as to:
(1) Make the interrogation and presentation effective for the
ascertainment of the truth,
(2) Avoid needless consumption of time, and
(3) Protect witnesses from harassment or undue embarrassment.
(b) Scope of cross-examination. Cross-examination should be limited
to the subject matter of the direct examination and matters affecting
the credibility of the witness. The judge may, in the exercise of
discretion, permit inquiry into additional matters as if on direct
examination.
(c) Leading questions. Leading questions should not be used on the
direct examination of a witness except as may be necessary to develop
the witness' testimony. Ordinarily leading questions should be permitted
on cross-examination. When a party calls a hostile witness, an adverse
party, or a witness identified with an adverse party, interrogation may
be by leading questions.
