A source of sound gives five beats per second when sounded with another source of frequency 100 s -1. The second harmonic of the source together with a source of frequency 205 s -1 gives five beats per second. What is the frequency of the source?

Question

A source of sound gives five beats per second when sounded with another source of frequency 100 s -1. The second harmonic of the source together with a source of frequency 205 s -1 gives five beats per second. What is the frequency of the source? (A) 105 s -1 (B) 205 s -1 (C) 95 s -1 (D) 100 s -1

Tardigrade Admin · Accepted Answer

Frequency of the source =100 ± 5=105 Hz or 95 Hz Second harmonic of the source =210 Hz or 190 Hz. As the second harmonic gives 5 beats/sec with sound of frequency 205 Hz, the second harmonic should be 210 Hz. ⇒ Frequency of the source =105 Hz

Q. A source of sound gives five beats per second when sounded with another source of frequency $100 s^{- 1}$ . The second harmonic of the source together with a source of frequency $205 s^{- 1}$ gives five beats per second. What is the frequency of the source?

$105 s^{- 1}$

$205 s^{- 1}$

$95 s^{- 1}$

$100 s^{- 1}$

Frequency of the source $= 100 \pm 5 = 105 Hz$ or $95 Hz$
Second harmonic of the source $= 210 Hz$ or $190 Hz$ .
As the second harmonic gives 5 beats/sec with sound of frequency $205 Hz$ , the second harmonic should be $210 Hz$ .
$\Rightarrow$ Frequency of the source $= 105 Hz$

Q. A source of sound gives five beats per second when sounded with another source of frequency 100s−1. The second harmonic of the source together with a source of frequency 205s−1 gives five beats per second. What is the frequency of the source?

105s−1

205s−1

95s−1

100s−1