Question

Q.In Quincke's tube a detector detects minimum intensity. Now one of the tube is displaced by 5 cm. During displacement detector detects maximum intensity 10 times, then finally a minimum intensity
(when displacement is complete). The wavelength of sound is:
(A) 10/9 cm (B) 1 cm
(C) 1/2 cm (D) 5/9 cm

Answer 1

Answer:

(B.) 1 cm ✔️

Explanation:

Given:

• In Quincke's tube a detector detects minimum intensity.
• Now one of the tube is displaced by 5 cm.
• During displacement detector detects maximum intensity 10 times, then finally a minimum intensity (when displacement is complete).

To find:

• The wavelength of sound.

Solution:

We know that during displacement detector detects maximum intensity 10 times and one of the tube is displaced by 5 cm, therefore, 10 maxima were found between points separated by 5 cm or while displacing one of the tube by 5 cm, so this distance is equal to 10 times half a wavelength.

Formula for maximum intensity sound changes:

♦ ΔP = n × λ/2

➾ 5 cm = 10 × λ/2

➾ 5 cm = 5 × λ

➾ λ = 5/5

➾ λ = 1 cm

Therefore, the wavelength of sound = 1 cm

_______________________

Answer 2

Given :-

In  Quincke's tube a detector detects minimum intensity. Now one of the tube is displaced by 5 cm. During displacement detector detects maximum intensity 10 times, then finally a minimum intensity

To Find :-

The wavelength of sound is:

Solution :-

We know that

P = n × λ/2

Where

P = Displace distance

n = Increase in maximum intensity

λ = Wavelength of sound

5 = 10 × λ/2

5/10 = λ/2

1/2 = λ/2

1 = λ

Hence

The Wavelength of sound is 1 cm. Option B