The Total solution for NCERT class 6-12
(i) आवृत्ति, n = 20 Hzवायु में ध्वनि का वेग = 344 ms-1υ = nλअथवा 344 = 20 x λअथवा λ = = 17.2m
(ii) आवृत्ति, n = 20 KHz = 20,000 Hzवायु में ध्वनि का वेग = 344ms-1υ = n x λ344 = 20,000 x λअथवा λ = =0.0172 m = 0.017 m