HPS202H1 Lecture : HPS202 Industrialization of Sound

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whiteshark471

13 Oct 2011

School

UTSG

Department

History and Philosophy of Science and Technology

Course

HPS202H1

Professor

G.Garbutt

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Document Summary

Phonograph first dev by edison 1877 as dictation machine: doesn"t see potential as mass product, dev for business purposes. 1887 bell takes over, works to produce mass market playback machine: public appeal demonstrated in exhibitions. 1900 dev of electroforming process to allow mass reproduction of records: decrease regional music but increase isolation of entertainment, i. e. jazz. 1902 recording by enrico caruso sells 1 million copies. 1914 phonograph well est as first home electronic entertainment device. 1880s james clerk maxwell and heinrich hertz perform experiments with producing and stabilizing electromagnetic waves. 1901 guglielmo marconi produces long distance wireless device, made use of morse telegraph key and morse code, designed for ship to shore communication, not expected to be tool of mass comm (require massive energy) 1913 research labs begin trying to create stable vacuum tube. Thursday, october 13, 2011: national broadcasting corporation, radio ntwk formed by rca, ge and.

Related Questions

Please solve all questions as early as possible.

(1). Light waves are electromagnetic waves that traval at 3. 00 x 10^8 m/s. The aye Is most sensitive to light having a wavelength of 5. 50 x 10^-7m. {a} Find the frequency of this light wave Hz =

Find the frequency of this light wave (HZ)
and its period(S).

2.The distance between two successive minima of a transverse wave is 3.00 m. Five full crest Intervals of the wave pass given point along the direction of travel every

14.2 s.

(a) Find the frequency of the wave Hz

(b} Find the wave speed m/s
3.
A harmonic wave bs traveling slong a repe It is observed that the oscillator that generates the wave completes 36.0 vibrations In 35.0 s Also, a given maximum travels 430 cm along the rope in 9.0 s What Is the wavelength in cm ?
4.
A bat can detect small objects, such as an insect, whose size is approximately equal to one wavelength of the sound the bat makes. If bats emit a chirp at a Frequency of

8.54 x 10^4 Hz, and if the speed of sound in air is 343 m/s, what is the smallest Insect a bat can detect in mm ?
5. A cork on the surface of 5 pond bobs up and down two times per second an Hippies having a wavelength of 9.50 cm .If the cork is 11.5 m fram shore, how long does it take a tipple passing the cork to reach the shore ?
( )S.

6. Ocean waves are traveling te the east at 4. 7 m/s with a distance of 19 m between crests. (a) With what frequency do the waves hit the front of a boat when the boat Is at anchor?
( ) HZ

(b) With what frequency do the waves hit the front of a boat when the boat Is moving westward at 1.5 m/s?
( ) HZ

7. A circus performer stretches s tightrope between two towers. He strikes ane end of the rope and sends a wave atong it toward the other tower He notes that It takes the

wave 0. 840 s to reach the opposite tower, 20.0 m away If s 1.00-m length of the rope has a mass of 0.260 kg, find the tension In the tightrope .
( ) N ?.

8. Transverse waves with a speed of 52. 0 m/s are to be produced on a stretched string A 5 .20-m length of string with a total mass of 0.0600 kg Is used.

{a) What is the required tension in the string?
( )N
(b} Calculate the wave speed in the string if the tension Is 8. 00 N.
( )m/s . ?

9.A wave of amplitude 0 .53 m interferes with a second wave of amplitude 0 .19 m traveling in the same direction.

(a) What Is the largest resultant amplitude that can occur, and under what conditions will this maximum arise?

( ) m

1.The two waves interfere destructively,

2.The two waves interfere constructively.

(b) What is the smallest resultant amplitude that cah occur, and under what conditions will this minimum arise?
( ) m

1.The two waves interfere destructively

2.The two waves interfere constructively

10. A certain tuning fork vibrates at a frequency of 161 Hz while each tip of Its two prongs has an amplitude of 0. 724 mm .

(a) What ts the per od of this motion?
( )ms .

(b) Find the wavelength of the sound produced by the vibrating fork taking the speed of sound in alr to be 343 m/s.
( ) m .

manya12

Please solve this as early as possible.

(1). Light waves are electromagnetic waves that traval at 3. 00 x 10^8 m/s. The aye Is most sensitive to light having a wavelength of 5. 50 x 10^-7m. {a} Find the frequency of this light wave Hz =

Find the frequency of this light wave (HZ)
and its period(S).

2.The distance between two successive minima of a transverse wave is 3.00 m. Five full crest Intervals of the wave pass given point along the direction of travel every

14.2 s.

(a) Find the frequency of the wave Hz

(b} Find the wave speed m/s
3.
A harmonic wave bs traveling slong a repe It is observed that the oscillator that generates the wave completes 36.0 vibrations In 35.0 s Also, a given maximum travels 430 cm along the rope in 9.0 s What Is the wavelength in cm ?
4.
A bat can detect small objects, such as an insect, whose size is approximately equal to one wavelength of the sound the bat makes. If bats emit a chirp at a Frequency of

8.54 x 10^4 Hz, and if the speed of sound in air is 343 m/s, what is the smallest Insect a bat can detect in mm ?
5. A cork on the surface of 5 pond bobs up and down two times per second an Hippies having a wavelength of 9.50 cm .If the cork is 11.5 m fram shore, how long does it take a tipple passing the cork to reach the shore ?
( )S.

A circus performer stretches s tightrope between two towers. He strikes ane end of the rope and sends a wave atong it toward the other tower He notes that It takes the

wave 0. 840 s to reach the opposite tower, 20.0 m away If s 1.00-m length of the rope has a mass of 0.260 kg, find the tension In the tightrope .
( ) N ?.

10.

A certain tuning fork vibrates at a frequency of 161 Hz while each tip of Its two prongs has an amplitude of 0. 724 mm .

(a) What ts the per od of this motlon?
( )ms .

(b) Find the wavelength of the sound produced by the vibrating fork taking the speed of sound in alr to be 343 m/s.
( ) m .

manya12

Vapor cycles
5EM - Thermodynamics
September 2010
1 The T-S diagram
The temperature-entropy diagram is an alternative to the well knownpressure-
volume diagram. Before using it to analyze different vapor cycles,we need
to understand it properly.
1. Plot the following transformations for ideal gases in a T-Sdiagram
(a) Isothermal expansion
(b) Isobaric expansion
(c) Isometric heating
(d) Reversible adiabatic expansion
(e) Irreversible adiabatic expansion
2. Repeat the last question, but this time do it for a realsubstance,
starting in the compressed liquid1 region and ending in thesuperheated
region, when possible. Indicate the boundaries of eachregion.
3. We know that under certain circumstances the area under theplot
in a P-V diagram represents the work performed during theprocess.
What does it represent in this case? Under what assumptions isyour
answer true? Compare examples 6.1 and 6.2.
2 Thermal machines
We understand by thermal machine a device capable of transformingther-
mal energy (heat) into mechanical energy (work). We already knowthat
these machines have a limited efficiency which, in the two-sourcesmodel, is
obtained by Carnotâs cycle.
(Compressed liquid is sometimes also called subcooled liquid)
2.1 Carnot cycle
This cycle, although efficient, is impractical. To begin with, theextreme
temperatures of the cycle should be within the sources temperaturesfor a
finite heat flow to exist.
1. Given the temperature of the sources, draw the cycle accordingto the
named limitation.
2. Show that this leads to lower efficiency than the theoreticallimit.
3. Assume that heat flow from/to the sources is proportional to thetem-
perature difference between them and the working fluid, anddemon-
strate that a higher power output is related to a decreasedefficiency.
2.2 Rankine cycle
Out of the several practical possibilities, Rankine cycle and itsvariations is
widely used, especially for electric power generation.
1. Draw the basic cycle in a T-S diagram and explain it.
2. What does the efficiency of the cycle depend on? Comparewith
Carnotâs.
3. What are the differences between the ideal cycle and the realone?
4. Describe how it is modified by superheating and/or reheating.Explain
te benefits.
2.3 Problems
After answering the previous questions solve the followingexercises from the
book: 8.2, 8.4, 8.5, 8.13, 8.19, 8.20
3 Frigorific machines
3.1 Reverse Carnot cycle
We have already studied Carnot cycle in detail as the ideal thermalmachine.
Now we will take is as the starting point to understand thecharacteristics
of frigorific machines.
1. Draw the ideal cycle in a T-S diagram and explain it.
2. Show that this cycle has a theoretical efficiency Ã =Tcold/Thot-Tcold
3. What are the difficulties in implementing such cycle in actualdevices?
3.2 Actual refrigerators
1. Why is the turbine replaced by an expansion valve in mostcases?
2. Plot the actual cycle and explain the differences with the idealcase.
3. How do cascade and multistage systems improve the performanceof
the refrigerator?
4. What aspects are important in the choice of a refrigerant fluid?Justify
3.3 Problems
After answering the previous questions solve the followingexercises from the
book: 10.2 10.7, 10.8, 10.9, 10.22, 10.23 10.1D

HPS202H1 Lecture : HPS202 Industrialization of Sound

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