In a transverse wave the distance between a crest and neighbouring trough at the same instant is 4.0 cm and the distance between a crest and trough at the same place is 1.0 cm. The next crest appears at the same place after a time interval of 0.4 s. The maximum speed of the vibrating particles in the medium is: (1) $\frac { 3\pi } { 2 } \mathrm {~cm} / \mathrm { s }$ (2) $\frac { 5\pi } { 2 } \mathrm {~cm} / \mathrm { s }$ (3) $\frac { \pi } { 2 } \mathrm {~cm} / \mathrm { s }$ (4) $2\pi \mathrm {~cm} / \mathrm { s }$
In a transverse wave the distance between a crest and neighbouring trough at the same instant is 4.0 cm and the distance between a crest and trough at the same place is 1.0 cm. The next crest appears at the same place after a time interval of 0.4 s. The maximum speed of the vibrating particles in the medium is:\\
(1) $\frac { 3\pi } { 2 } \mathrm {~cm} / \mathrm { s }$\\
(2) $\frac { 5\pi } { 2 } \mathrm {~cm} / \mathrm { s }$\\
(3) $\frac { \pi } { 2 } \mathrm {~cm} / \mathrm { s }$\\
(4) $2\pi \mathrm {~cm} / \mathrm { s }$