Zubin Mehta made his first appearing in Washington as conductor of the New York Philharmonic last night at the Kennedy Center, and he devoted the occasion to a largely choral program.

The 200 voices of the Westminster Choir joined the orchestra for performances of Bernstein's "Chichester Psalms" and the Verdi Four Sacred Pieces, which outlined quite clearly Mehta's strengths and weakness.

This is a choir that is schooled in a refined choral tradition that stresses lightness, accuracy, blend and balance. Under Mehta's direction they move litingly through the Bernstein Psalms taking the rhythmic sections with a breathless speed that managed, somehow, to remain both clear and in control.

The Verdi moved the same way, and therein lies Mehta's weakness. He seems to be an entirely objective conductor, achieving marvelous dramatic effects when the composer has provided the dynamic fireworks and the flashy instrumentation.

Where the resources are more sbtle, however, where the drama resides in the flexibility of phrasing and in the treatment of diction and pure sound reproduction, as in the Verdi, he seems to lack the subjective approach needed to allow the music to speak idiomatically.

He also took a needlessly dangerous gamble by having the four Verdi pieces follow one another without instrumental pitches between. The ghastly pitch discrepancies as the instruments entered the Te Deum, after minutes of a capella singing, proved the gamble wasn't worth it.

Twelve-year-old alto Victor Cook handled the solo in the Bernstein with professional aplomb.

The concert opened with a nicely paced performance of the Shubert "Unfinished" Symphony.