BSE Odisha Class 8 Science Chapter 10: Sound (ଶବ୍ଦ)

Mastering the concepts of Sound is essential for understanding how we communicate and perceive the world around us. At Odisha Board Solutions, we provide simplified, stepwise answers for Class 8 Science Chapter 10, specifically updated for the 2026-27 session.

1. How is Sound Produced? (ଶବ୍ଦ କିପରି ସୃଷ୍ଟି ହୁଏ?)

Sound is produced by vibrating objects. A vibration is a rapid back-and-forth motion of an object.

- In Humans: Sound is produced by the Larynx (ସ୍ୱରପେଟୀ) or Voice Box.
- In Instruments: Sound is produced by vibrating strings (Sitar), membranes (Tabla), or air columns (Flute).

2. Propagation of Sound (ଶବ୍ଦର ସଞ୍ଚରଣ)

Sound needs a medium (solid, liquid, or gas) to travel. It cannot travel through a vacuum (ଶୂନ୍ୟସ୍ଥାନ) because there are no molecules to carry the vibrations.

Speed of Sound: Sound travels fastest in solids and slowest in gases.

3. Characteristics of Sound (ଶବ୍ଦର ବିଶେଷତ୍ୱ)

To distinguish one sound from another, we look at three main properties:

Amplitude (ବିସ୍ତାର): Determines the Loudness of the sound. Larger amplitude means louder sound (measured in decibels, dB).
Frequency (କମ୍ପନାଙ୍କ): Determines the Pitch (ଶାଣିତପଣ). Higher frequency means a shriller or higher-pitched sound (measured in Hertz, Hz).
Time Period: The time taken to complete one full vibration.

4. The Human Ear (ମଣିଷ କାନ)

The human ear is a sensitive organ that converts sound vibrations into electrical signals for the brain.

1. Outer Ear (Pinna): Collects sound waves.
2. Middle Ear: Contains the Eardrum (କର୍ଣ୍ଣପଟହ) which vibrates when hit by sound.
3. Inner Ear: Sends signals to the brain via the auditory nerve.

5. Audible and Inaudible Sounds

Audible Range: The human ear can hear frequencies between 20 Hz and 20,000 Hz.
Infrasonic: Sounds below 20 Hz.
Ultrasonic: Sounds above 20,000 Hz.

6. Download Class 8 Science Chapter 10 PDF (Odia Medium)

We offer a FREE PDF Download of the Class 8 Science Chapter 10 Questions and Answers. This flattened PDF is optimized for Odia medium students to ensure all diagrams and scripts are perfectly clear, helping you maintain a high-quality standards.

Revision Tip: Pay close attention to the definition of Noise Pollution (ଶବ୍ଦ ପ୍ରଦୂଷଣ) and its harmful effects on health, as this is a frequent “Long Answer” question in the BSE Odisha exams.