(Figure 1) shows the circular wave fronts emitted by two wave sources. Are these sources in phase or out of phase? Make a table with rows labeled P, Q, and R and columns labeled r1, r2, Δr, and C/D. Fill in the table for points P, Q, and R, giving the distances as multiples of λ and indicating, with a C or a D, whether the interference at that point is constructive or destructive.

(Figure 1) shows the circular wave fronts emitted by two wave sources. Are these sources in phase or out of phase? Make a table with rows labeled P, Q, and R and columns labeled r1, r2, Δr, and C/D. Fill in the table for points P, Q, and R, giving the distances as multiples of λ and indicating, with a C or a D, whether the interference at that point is constructive or destructive.