Q76 / 90 · JEE Main 2014 (19 Apr Online) · Physics
The total length of a sonometer wire fixed between two bridges is . Now, two more bridges are placed to divide the length of the wire in the ratio . If the tension in the wire is and the mass per unit length of the wire is , then the minimum common frequency with which all the three parts can vibrate, is
- Correct answerA
- B
- C
- D
Solution
The frequancy in any mode for a segment is
no of loops ∝ length of the segment
so, no of loops are in the ratio 6:3:2
hence total loops =11
The string is divided in 60 cm, 30 cm, & 20 cm part such that for minimum frequency, the wavelength is maximum
Hence, the correct answer is option: 'A'.