1.
Which among the following statements is TRUE about sound?
Correct Answer
B. The more an object vibrates, the louder is the sound.
2.
Which among the following is TRUE about frequency?
Correct Answer
C. Faster vibrations give high frequency.
Explanation
Faster vibrations give high frequency because frequency is defined as the number of vibrations or cycles per unit of time. When vibrations occur more quickly, there are more cycles happening in a given amount of time, resulting in a higher frequency.
3.
Which among the following vibrations do humans can hear?
Correct Answer
B. 22 vibrations per second
Explanation
Humans can hear vibrations within a specific range called the audible frequency range. This range typically falls between 20 and 20,000 vibrations per second, or hertz (Hz). The answer "22 vibrations per second" falls within this audible frequency range and is therefore the correct answer.
4.
Why do we usually see a flash of lightning before we hear thunder?
Correct Answer
C. Sound travels faster than light.
Explanation
The given answer is incorrect. In reality, light travels much faster than sound. The reason we usually see a flash of lightning before hearing thunder is because light travels faster than sound. Light waves travel at a speed of approximately 299,792 kilometers per second, while sound waves travel at a speed of around 343 meters per second. Therefore, the light from the lightning reaches our eyes almost instantly, while the sound takes longer to reach our ears, resulting in the delay between seeing the flash and hearing the thunder.
5.
How can you reduce the echoes in your room?
Correct Answer
D. Use curtains and rugs.
Explanation
Using curtains and rugs can help reduce echoes in a room because they absorb sound waves and prevent them from bouncing off hard surfaces. Curtains can be hung on walls or windows to absorb sound, while rugs can be placed on the floor to absorb sound vibrations. By reducing the amount of sound reflection, curtains and rugs create a more acoustically balanced environment, reducing echoes and improving the overall sound quality in the room.
6.
How can one minimize noise?
Correct Answer
C. Avoid making unnecessary noise.
Explanation
To minimize noise, it is important to avoid making unnecessary noise. This means refraining from activities that create loud or disruptive sounds, such as banging objects, playing loud music, or engaging in noisy conversations. By being mindful of one's actions and surroundings, and making an effort to keep noise levels low, a quieter and more peaceful environment can be achieved.
7.
Check the properties of sound.
Correct Answer(s)
B. Sound can be absorbed.
C. Sound can be reflected.
D. Sound travels through air, water, and solids.
F. The pitch and loudness can be modified.
Explanation
The correct answer is that sound can be absorbed, sound can be reflected, sound travels through air, water, and solids, and the pitch and loudness can be modified. This is because sound waves can be absorbed by certain materials, such as foam or fabric, causing the sound to decrease in intensity. Sound waves can also be reflected off surfaces, like walls or mirrors, causing an echo or reverberation. Additionally, sound waves can travel through different mediums, including air, water, and solids. Lastly, the pitch and loudness of sound can be altered by changing the frequency and amplitude of the sound waves respectively.