Sound quiz

Sound is produced by:

The voice box in humans is called the:

Sound cannot travel through:

The SI unit of frequency is:

The loudness of sound depends on its:

The pitch of sound depends on its:

The audible range of frequencies for humans is about:

The part of the ear that vibrates when sound falls on it is the:

Which of these is a measure to reduce noise pollution?

A vibrating body makes 100 vibrations per second. Its frequency is:

What is the vibrating part in (i) a guitar (ii) a whistle? (2 marks)

Why are the voices of women generally higher in pitch than those of men? (2 marks)

How can you show that sound travels through solids? (2 marks)

What is the relation between frequency and time period? (2 marks)

Distinguish between music and noise. (2 marks)

Name two animals that can hear ultrasonic sounds. (2 marks)

Why should we not put sharp objects into our ears? (2 marks)

What is an oscillation? Give one example. (2 marks)

Why does a ringing bell stop producing sound when you touch it? (2 marks)

Give two uses of ultrasound. (2 marks)

A pendulum oscillates 30 times in 6 seconds. Find its time period and frequency. (3 marks)

The frequency of a vibrating string is 400 Hz. Find its time period. How many vibrations will it make in 5 seconds? (3 marks)

The time period of a sound wave is 0.04 s. Find its frequency and state whether it is audible. (3 marks)

The amplitude of a sound is made 4 times its original value. By what factor does its loudness change? If the amplitude is halved instead, what happens to the loudness? (3 marks)

Classify the following frequencies as infrasonic, audible or ultrasonic: 10 Hz, 256 Hz, 15,000 Hz, 40,000 Hz, 5 Hz, 1,00,000 Hz. (3 marks)

Read the passage and answer the questions. Boojho placed a ringing mobile phone inside a glass jar and slowly pumped out the air. The sound became fainter and fainter, although he could still see the screen lighting up. (i) Why did the sound become fainter? (ii) What does this experiment show about the propagation of sound? (iii) Why could he still see the screen? (5 marks)

Read the passage and answer the questions. In a music class, a teacher plucked a sitar string gently and then strongly. Later she shortened the vibrating length of the string by pressing it with her finger. (i) What changed when she plucked the string strongly? (ii) What happened to the pitch when the string was shortened? (iii) Name the property of the vibration responsible for each change. (5 marks)

Read the passage and answer the questions. Residents near an airport complained of headaches, sleeplessness and irritation. A survey showed that noise levels near their homes often exceeded 80 dB. (i) What is this problem called? (ii) Name two health effects of prolonged exposure to loud noise. (iii) Suggest two measures to reduce the problem. (5 marks)

Read the passage and answer the questions. Paheli held a metre scale firmly on the edge of a table and pressed its free end. The scale vibrated and produced a sound. When she reduced the length of the free end, the sound changed. (i) What produced the sound? (ii) How did the sound change when the free length was reduced? (iii) Explain the change in terms of frequency. (5 marks)

Read the passage and answer the questions. A child put one ear against a long iron railing while his friend tapped the far end with a stone. He heard the tap clearly through the railing, before he heard it through the air. (i) What does this show about sound in solids? (ii) In which medium did sound travel faster? (iii) Why is it dangerous to try this on a railway track? (5 marks)

Draw a labelled diagram of the human ear. Explain how sound reaches the eardrum and how we hear. Give three ways to protect our ears. (6 marks)

Draw a labelled diagram of the human larynx showing the vocal cords. Explain how voice is produced and why voices differ in pitch among people. (6 marks)

Draw wave diagrams to show the difference between (i) a loud and a soft sound (ii) a high pitched and a low pitched sound. Explain amplitude, frequency, loudness and pitch with the help of your diagrams. (6 marks)

Describe, with a labelled diagram, an activity to show that sound needs a medium to travel. Also describe how you would show that sound travels through water. (6 marks)

Draw a flowchart showing the sources, effects and control measures of noise pollution. Explain each with at least two examples. (6 marks)