experiment 7 : waves and sound

Question 1

it is the maximum excursion of a particle of the medium from the particles undisturbed position.

Answer 1

amplitude
[Imagine a wave going up and down. The amplitude is how high or low the wave goes from the middle. It’s like how far you can swing on a swing set from your resting spot.]

Question 2

it is the horizontal length of one cycle of the wave.

Answer 2

wavelength
[This is the distance between one “wave bump” and the next one—like from one peak to the next or one dip to the next. Think of it as the space between two waves on the ocean.]

Question 3

it is the time required for one complete cycle.

Answer 3

period

Question 4

it is related to the period and has units of Hz, or s-1.

Answer 4

frequency
[This tells you how many waves pass by in a second. If one wave takes a second, the frequency is 1 wave per second (1 Hz). It’s the speed of the waves in terms of how often they come.]

Question 5

amplitude:
wavelength:
period:
frequency:

Answer 5

Amplitude: How tall the wave is.
Wavelength: How long the wave is.
Period: How much time one wave takes.
Frequency: How many waves in a second.

Question 6

formula of frequency

Answer 6

f = 1/T
Frequency (f) is how many waves happen in one second (measured in Hertz, Hz).
Period (T) is how much time it takes for one wave to happen (measured in seconds).

If a wave takes a long time (big T), fewer waves fit in one second (small f).
If a wave happens quickly (small T), more waves fit in one second (big f).

Question 7

this has many natural modes of vibration

Answer 7

stretched string

Question 8

What happens when the string is fixed at both ends

Answer 8

At the ends of the string, the vibration can’t move up or down. These points are called nodes
The string can vibrate in different ways, like wiggling as one big hump or splitting into smaller humps.

Question 9

what happens if the string vibrates as one big hump

Answer 9

single segment
The length of the string (L) is half the length of one full wave (λ, the wavelength).
In simple terms, it takes two strings’ worth to make a full wave.

Question 10

what are the points that dont move at the ends of the string, and sometimes in the middle too

Answer 10

nodes

Question 11

what happens with
2 segments:

more segments:

Answer 11

2 segments:
string splits into two equal parts, with one node in the middle
the length of the string (L) equals one full wavelength (λ) because two segments make up a full wave

more segments:
string can vibrate in 3, 4, or more segments, creating more nodes along the string the length of the string (L) is always equal to some whole number (integer) of half-wavelengths.

Question 12

1 segment: L =
2 segments: L =
3 segments: L =
4 segments: L =

Answer 12

1 segment: L = 1/2 λ
2 segments: L = λ
3 segments: L = 3/2 λ
4 segments: L = 2 λ
and so on!

Question 13

What happens if you vibrate a string at an arbitrary (random) frequency?

Answer 13

Many vibration patterns (modes) mix together, and no single mode stands out.

Question 14

How can you make a string vibrate strongly in just one mode?

Answer 14

Adjust the string’s tension and length to match the frequency of the force driving the vibration.

Question 15

What is it called when a string vibrates strongly in one clear mode?

Answer 15

Resonance

Question 16

What happens to the amplitude of the vibration during resonance?

Answer 16

It becomes much greater (the string vibrates more strongly).

Question 17

how do you get the mass of string

Answer 17

using top balance

Question 18

purpose of
force sensor:
string vibrator:
sine wave generator:

Answer 18

force sensor:
measures the tension (tightness) in the string.

string vibrator:
device that shakes the string at a specific frequency

sine wave generator:
to control the frequency at which the string vibrator shakes the string
produces a smooth, repeating wave (a sine wave), which tells the vibrator how fast to move the string up and down.

Question 19

what equipment is used to adjust the frequency to produce first 3 modes of vibration

Answer 19

sine wave generator

Question 19

what is the purpose of the economy resonance tube

Answer 19

it is used to study how sound waves behave in a column of air and to measure the speed of sound.

Question 20

What are the two parts of the Economy Resonance Tube?

Answer 20

The outer tube and the inner tube with a scale and a removable plug.

Question 21

How is the length of the air column adjusted in the resonance tube?

Answer 21

By moving the inner tube to change the length of the air column.

Question 22

What happens when the plug is in place in the resonance tube?

What happens when the plug is removed from the resonance tube?

Answer 22

The tube is closed at one end.

The tube is open at both ends.

Question 23

What is the purpose of the scale on the resonance tube?

Answer 23

To measure the resonating length of the air column, with two rows: one for when the plug is in place and one for when the plug is removed.

Question 24

Using Temperature to Find the Speed of Sound

Answer 24

v=331.45m/s+0.61T(°C)
v is the speed of sound in meters per second (m/s).
T is the temperature in Celsius (°C).

At 0°C, the speed of sound is 331.45 m/s. For every degree above 0°C, the speed increases by 0.61 m/s. For example:

At 20°C, the speed of sound is:
v=331.45+(0.61×20)=343.45m/s

Question 25

Using Wavelength and Frequency to Find the Speed of Sound

Answer 25

v=fλ
v is the speed of sound (m/s).
f is the frequency of the sound (in Hz, or waves per second).
λ (lambda) is the wavelength (the length of one wave).

To find the speed of sound, you just multiply the frequency by the wavelength.
For example, if the frequency is 500 Hz and the wavelength is 0.7 meters:
v=500×0.7=350m/s