NIOS Class 10 Science Activity 18.2 Solution-Sound and Communication Explained

In this activity, we will learn how the pitch of a sound depends on the length and tension of a vibrating string.

Sound and Communication Activity Solution

This activity is based on the NIOS Class 10 science and technology (212) Chapter 18- Sound and Communication Module 4- Energy

Relation of Pitch and Wavelength of Sound

Aim

To understand the relation between the pitch of the sound and the wavelength

Materials Required

   1. Hollow metallic box or wooden box

   2. Three metallic strings or wires

   3. Hammer

   4. Iron nails

   5. Adhesive

Procedure

We take a hollow metallic box or wooden box and fix three pairs of nails on it at different distances, for example, 10 cm, 20 cm, and 30 cm, using a hammer. After that, we stretch one metallic string or wire tightly between each pair of nails separately.

 Now we pluck each string one by one and listen carefully to the sound. We observe the sound produced by each string separately.

Observation

   1. Each string produces a different sound when plucked.

   2. The shorter string produces a higher–pitched sound.

   3. The longer string produces a lower-pitched sound.

Explanation

When we pluck a string, it starts vibrating and produces sound. The frequency of vibration depends on the length of the string.

 A shorter string vibrates more quickly and produces a higher frequency and a higher-pitched sound.

A longer string vibrates slowly and produces a low-frequency, low-pitch sound.

The frequency depends on the tension in the vibrating string. If the tension is increased, the vibration becomes faster and produces a higher pitch.

If we fill glass or steel tumblers with water to different levels and strike them with a spoon, then each tumbler produces a sound of a different pitch. The tumbler with a higher water level (short air column) produces a higher pitch, while the one with a low water level (long air column) makes a sound of low pitch.

Conclusion

 We can conclude that the short vibrating string produces a higher pitch of the sound while the longer string produces a lower pitch sound. The pitch of sound increases with an increase in tension in the vibrating string.

Frequently Asked Questions

   1. What happens when we pluck strings of different lengths?

Answer – Each string produces a sound of a different pitch.

   2. Which string produces a higher-pitched sound?

Answer – The shorter string produces a higher-pitched sound.

   3. Does the tension in the string affect the pitch?

Answer – Yes, higher tension increases frequency and produces a higher pitch.