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Characteristics of forced vibrations : 

1. The body acquires the frequency of external periodic force. 

2. The amplitude of forced vibration is very small, if the frequency of external force is much different from natural frequency of the body. 

3. The amplitude of vibration remains constant with time, but magnitude depends upon the frequency of the driving force. 

4. If the frequency of external force is exactly equal or is an integral multiple vibrating body, the amplitude of oscillation is very large. 

(i) The vibrations of a body in the absence of any resistive force are called the free vibrations. The vibrations of a body in the presence of an external force are called forced vibrations.

(ii) In free vibrations, the frequency of vibration depends on the shape and size of the body. In forced vibrations, the frequency is equal to the frequency of the force applied.

The shrillness of sound is the characteristic property of sound which differentiates the sound between male and female. Usually the voice of a woman has higher frequency and shriller than the voice of a man.

The length of vocal chords varies in all these three, which is the main reason for different voices. Men have the longest vocal chords, while female have little shorter vocal chords than men and children have the smallest vocal chords.

(a) True 

(b) False 

(c) False 

(d) True 

(e) False 

(f) False 

(g) True 

Yes, it is true. We already know a vibrating object produce sound. Sound is a mechanical wave that can produce vibration. (Mechanical waves have ability to vibrate an object)

True 

Explanation: 

Given, 

Frequency(f) = 300 Hz 

No. of vibration = 30 

Distance travelled by sound = 34 m

frequency(f) = \(\frac{1}{Time\,period(T)}\)

⇒ T = \(\frac{1}{f}\)

⇒ T = \(\frac{1}{300}\) = 0.0033 sec

After 30 vibrations, 

Total time taken = No. of vib.×Time period

Total time taken = 30 × \(\frac{1}{300}\)  = 0.1 s

Distance travelled = speed × time 

Distance = 340×0.1 = 34 m

Unit of loudness - decible(dB)

Correct option is C) 1-True, 2-False

The sounds which are heard easily, are loud sounds and the sounds which cannot be heard unless we listen attentively, are soft sounds.

B) Lion < Adult men < Adult women < infant

Correct Answer is: (c) 

The voice of a man is of lower pitch as compared to voice of a baby girl, baby boy or a woman. Since frequency of sound is directly proportional to its pitch, man’s voice is of minimum frequency as compared to others.

The sounds which have greater amplitude are louder.

As amplitude of vibration increases the intensity of sound increases.

Eardrum: The thin membrane at the end of the auditory canal.

The shrillness of a sound is known as pitch.

The pitch of the voices depend on frequency. As the number of vibrations per second increases the pitch or shrillness increases. So insect produce shrillness due to more frequency of vibration.

The sounds which have low amplitude are feeble.

Loudness: Loudness or softness of sound depends on upon amplitude. Loud sounds are having greater amplitude

Feeble: Sounds of low amplitude

Pitch (Shnllness): The shrillness of a sound known as pitch (or) Sound of higher frequency produce shrillness

Frequency: The number of vibrations per second is called frequency.

Amplitude: The maximum displacement of the vibrating body from its mean position is colled amplitude.

Decibel: Decibel is the unit for measuring the intensity of sound

A. Amplitude

The loudness of a sound is directly proportional to its amplitude.

The correct answer is d) S

The correct answer is c) increases

C) a – ii, b – i, c – iii

SONAR is equipment or a system for finding objects underwater using sound waves.

Correct option is  C) frequency

Correct option is: (A) 395 m

Musical sound:

1. It is pleasant to hear.

2. The pitch and loudness do not change suddenly.

3. The sound is repeated periodically.

Noise:

1. Jarring and unpleasant to hear.

2. The pitch and loudness change very much.

3. There is no periodic repetitions of frequency.

The outer ear is called pinna. It collects the sound from the surroundings and passes on to the eardrum through the auditory canal. The vibrations in the eardrum are amplified by Three bones, (the hammer, anvil and stirrup) in the middle ear.

C) Unique and different textures can be created through blending

The number 256 on the tuning fork signifies the frequency of the tuning fork.

Correct option is A) 0 meter/sec

Sound travels faster in hydrogen.

Correct option is A) Solids

Correct option is  A) solids