27) G

**P – Wrong**

We can immediately eliminate P since speed of sound in air = 330m/s

**Q – Wrong**

Amplitude is the distance between 0 and maximum displacement. Here the amplitude would be half of the distance travelled by the wave, i.e. ½ x 5 = 2.5mm

**R – Wrong**

We first need to know the frequency of the sound wave to find the wavelength.

Frequency = 1 ÷ T = 1/(2 ÷ 1000) = 5000 Hz

Speed = Frequency x Wavelength

Wavelength = Speed ÷ Frequency = 330 ÷ 5000 = 0.066m = 66mm (hence 5.5mm is wrong)

**S – Correct**

Frequency = 1 ÷ T = 1/(2 ÷ 1000) = 5000 Hz = 5 kHz

Since only statement S is wrong, G is the correct answer.

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