Verified Solution • 2025–26 Session moderate

QJEEM19Ph4f63: JEE Main 2019 Physics - Class 11 JEEM19Ph4f63 Solution: A string 2.0 m long and fixed at its ends is driven by a 240 Hz …

A string 2.0 m long and fixed at its ends is driven by a 240 Hz vibrator. The string vibrates in its third harmonic mode. The speed of the wave and its fundamental frequency is :-

Multiple Choice Options

  • A 180m/s, 80 Hz
  • B 180m/s, 120 Hz
  • C 320m/s, 120 Hz
  • D 320m/s, 80 Hz

Step-by-Step Verified Solution

We have:

f=nv2l

240=3×v2×2

⇒ v = 320 m/s

Fundamental frequency = v2l = 80 Hz.

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