JEE Challenger
More from Waves

Match Standing Wave Systems with Wave Properties and Wavelength

Column I shows four systems, each of the same length L, for producing standing waves. The lowest possible natural frequency of a system is called its fundamental frequency, whose wavelength is denoted as λf\lambda_f. Match each system with statements given in Column II describing the nature and wavelength of the standing waves.

Column I

(A) Pipe closed at one end

Diagram 0

(B) Pipe open at both ends

Diagram 1

(C) Stretched wire clamped at both ends

Diagram 2

(D) Stretched wire clamped at both ends and at mid-point

Diagram 3

Column II

(p) Longitudinal waves

(q) Transverse waves

(r) λf=L\lambda_f = L

(s) λf=2L\lambda_f = 2L

(t) λf=4L\lambda_f = 4L

Options

A

(A)→(P),  (B)→(P,S),  (C)→(Q,S),  (D)→(Q,R)(\text{A}) \rightarrow (\text{P}),\; (\text{B}) \rightarrow (\text{P}, \text{S}),\; (\text{C}) \rightarrow (\text{Q}, \text{S}),\; (\text{D}) \rightarrow (\text{Q}, \text{R})

B

(A)→(P,T),  (B)→(S),  (C)→(Q),  (D)→(Q,R)(\text{A}) \rightarrow (\text{P}, \text{T}),\; (\text{B}) \rightarrow (\text{S}),\; (\text{C}) \rightarrow (\text{Q}),\; (\text{D}) \rightarrow (\text{Q}, \text{R})

C

(A)→(P,T),  (B)→(P,S),  (C)→(Q,S),  (D)→(Q,R)(\text{A}) \rightarrow (\text{P}, \text{T}),\; (\text{B}) \rightarrow (\text{P}, \text{S}),\; (\text{C}) \rightarrow (\text{Q}, \text{S}),\; (\text{D}) \rightarrow (\text{Q}, \text{R})

Correct
D

(A)→(T),  (B)→(P),  (C)→(Q,S),  (D)→(R)(\text{A}) \rightarrow (\text{T}),\; (\text{B}) \rightarrow (\text{P}),\; (\text{C}) \rightarrow (\text{Q}, \text{S}),\; (\text{D}) \rightarrow (\text{R})

Step-by-Step Solution

To match each system in Column I with its appropriate wave properties and fundamental wavelength in Column II, we analyze the nature of the waves (longitudinal vs. transverse) and the boundary conditions for each standing wave system:


System (A): Pipe closed at one end

  1. Wave Nature: Sound waves in air columns are pressure/displacement waves that oscillate parallel to the direction of wave propagation, making them longitudinal waves →\rightarrow (p).
  2. Fundamental Wavelength (λf\lambda_f): A closed pipe of length LL has a displacement node at the closed end (x=0x = 0) and a displacement antinode at the open end (x=Lx = L). For the fundamental mode (lowest natural frequency):
    L=λf4  ⟹  λf=4L→(t)L = \frac{\lambda_f}{4} \implies \lambda_f = 4L \rightarrow \mathbf{(t)}

Thus, (A) →\rightarrow (p, t).


System (B): Pipe open at both ends

  1. Wave Nature: Waves inside the open pipe are sound waves in air, which are longitudinal waves →\rightarrow (p).
  2. Fundamental Wavelength (λf\lambda_f): An open pipe of length LL has displacement antinodes at both open ends (x=0x = 0 and x=Lx = L) and a single node at the center. For the fundamental mode:
    L=λf2  ⟹  λf=2L→(s)L = \frac{\lambda_f}{2} \implies \lambda_f = 2L \rightarrow \mathbf{(s)}

Thus, (B) →\rightarrow (p, s).


System (C): Stretched wire clamped at both ends

  1. Wave Nature: Waves on a stretched string/wire oscillate perpendicular to the length of the string, making them transverse waves →\rightarrow (q).
  2. Fundamental Wavelength (λf\lambda_f): Clamped fixed ends force displacement nodes at x=0x = 0 and x=Lx = L. The fundamental mode contains a single antinode at the center:
    L=λf2  ⟹  λf=2L→(s)L = \frac{\lambda_f}{2} \implies \lambda_f = 2L \rightarrow \mathbf{(s)}

Thus, (C) →\rightarrow (q, s).


System (D): Stretched wire clamped at both ends and at mid-point

  1. Wave Nature: Standing waves on a stretched wire are transverse waves →\rightarrow (q).
  2. Fundamental Wavelength (λf\lambda_f): Clamping the wire at x=0x = 0, x=L/2x = L/2, and x=Lx = L forces fixed displacement nodes at these points, dividing the wire into two independent segments each of length l=L2l = \frac{L}{2}. For the lowest possible natural frequency of this clamped system, each segment vibrates in its fundamental mode:
    l=L2=λf2  ⟹  λf=L→(r)l = \frac{L}{2} = \frac{\lambda_f}{2} \implies \lambda_f = L \rightarrow \mathbf{(r)}

Thus, (D) →\rightarrow (q, r).


Final Matching Summary:

  • (A) →\rightarrow p, t
  • (B) →\rightarrow p, s
  • (C) →\rightarrow q, s
  • (D) →\rightarrow q, r