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.