MHT CET202521 Apr 2025Evening ShiftPhysicsWaves and SoundActual
Two strings ' X ' and ' Y ' of a guitar produces a beat frequency of 6 Hz . When the tension of the string ' Y ' is increased, the beat frequency is found to be 4 Hz . If the frequency of string ' X ' is 300 Hz , then the original frequency of string ' Y ' is
Options
- A296 Hz
- B294 Hz
- C306 Hz
- D304 Hz
Correct answer
B. 294 Hz
Step-by-step solution
Given f_X = 300 Hz produces a beat frequency of 6 Hz with string Y, the original frequency f_Y satisfies |300 - f_Y| = 6 . This yields possible values f_Y = 294 Hz or f_Y = 306 Hz . Increasing tension raises the frequency of string Y. With the new beat frequency reduced to 4 Hz , the updated frequency f_Y' satisfies |300 - f_Y'| = 4 , giving possible values f_Y' = 296 Hz or f_Y' = 304 Hz . Since f_Y' > f_Y under increased tension, the case f_Y = 306 Hz is invalid—neither 296 Hz nor 304 Hz exceeds 306 Hz . Only f_Y