Science Question Answer (5 Marks)

The four sources of sound in a market place are:

1. Vendors selling eatables or other things.
2. Shopkeepers selling their things.
3. Vehicles in the market area, example, autorickshaw, car, etc.
4. Machines or generators noise.

1. Guitar, Veena.
2. Flute, Trumpet.
3. Tabla, Dholak.
4. Cymbals, Matka.

In humans, the sound is produced by the box, which is called voice box or the larynx. Larynx is a part of the throat. It is responsible for production of sound. It has two vocal cord which are stretched across the voice box or larynx in such a way that it leaves a narrow slit between them for the air. When the lungs force the air through the slit, the vocal cords vibrate, producing sound.

In humans, the sound is produced by the box, which is called voice box or the larynx. Larynx is a part of the throat. It is responsible for production of sound. It has two vocal cord which are stretched across the voice box or larynx in such a way that it leaves a narrow slit between them for the air. When the lungs force the air through the slit, the vocal cords vibrate, producing sound.

The harmful and annoying noise to the ears is called noise pollution. The sources of noise pollution are as follows:

1. Televisions running at high volumes.
2. Use of Loudspeakers in religious or other functions.
3. Use of crackers.
4. Horns of buses, cars and trucks.

1. Hammer, Anvil, Stirrup are the three ear bones.
2. Strirrup is in touch with oval window.
3. Hammer is in touch with the ear drum.
4. Anvil is in touch with the other two bones.

1. Veena.
2. Flute.
3. Table.
4. Cymbals.

The bell jar experiment is a common experiment to show that sound cannot travel through a vacuum. A bell jar’s shape is similar to that of a bell. A bell jar is placed on a base and connected to a vacuum pump as shown in the picture below. The air in the jar is varied by pumping the air out of it.
Now, we put an electrical bell in the bell jar. As the air is pumped, vacuum is being created inside the jar slowly and steadily and the sound from the bell jar fades. At a point when complete vacuum is maintained, no more sound is heard from the bell. Thus, the sound is not audible to our ears because of the vacuum inside the jar.

The ear has three main parts:

1. External part - It is called the pinna and is made of ridged cartilage covered by skin.
2. Middle - This is the part through which sound travels inside the ear to the eardrum, through auditory canal. Sound causes the eardrum and its tiny attached bones in the middle portion of the ear to vibrate, and the vibrations are conducted to the nearby cochlea.
3. Inner part - The cochlea is part of the inner ear. Its main function is to transform sound into nerve impulses.

1. Cannot be heard because human being can hear within the range 20Hz to 20,000Hz.
2. Can be heard because human being can hear within the range 20Hz to 20,000Hz.
3. Can be heard because human being can hear within the range 20Hz to 20,000Hz.
4. Cannot be heard because human being can hear within the range 20Hz to 20,000Hz.
5. Can be heard because human being can hear within the range 20Hz to 20,000Hz.

1. Strings.
2. Diaphragm – Membrane.
3. Air column.
4. The metal plates.
5. Strings.
6. Diaphragm – Membrane.