# A bothersome feature of many physical measurements is the presence of a background signal (commonly called "noise"). It is necessary, therefore, to subtract off this background level from the data to obtain a valid measurement. Suppose the measured background level

12,888 results
1. ## Physics

A bothersome feature of many physical measurements is the presence of a background signal (commonly called "noise"). It is necessary, therefore, to subtract off this background level from the data to obtain a valid measurement. Suppose the measured

asked by Marissa on October 9, 2009
2. ## physics

A bothersome feature of many physical measurements is the presence of a background signal (commonly called "noise"). In Part 2.2.4 of the experiment, some light that reflects off the apparatus or from neighboring stations strikes the photometer even when

asked by anna on June 29, 2010
3. ## Physics

In the experiment, a meter is hooked up to a speaker to monitor the amplitude of the received sound. Suppose the background signal level is 15 mV, the signal is 90 mV with no attenuator and is 30 mV with an attenuator in place. Calculate pt/pi including

asked by Michael on November 28, 2011
4. ## Physics

In the experiment, a meter is hooked up to a speaker to monitor the amplitude of the received sound. Suppose the background signal level is 15 mV, the signal is 90 mV with no attenuator and is 30 mV with an attenuator in place. Calculate pt/pi including

asked by Michael on November 16, 2011
5. ## chemistry

What type of feature will be observed in the EI mass spectrum of chlorobenzene? An absorption at 3100 cm–1 No signal at all A signal at 112 and a signal at 114 in a ratio of 3:1 A signal at 112 and a signal at 114 in a ratio of 1:1

asked by Tiffany on December 12, 2011
6. ## Chemistry

Why wasn't information about the mass of isotopes sufficient for identifying the isotopes? Provide an example to explain the answer. Figure 2 shows 2.5 min averaged spectra of ambient aerosol at nominal m/z 208 obtained with the HR-AMS located at T0. Panel

asked by Joe on October 28, 2017
7. ## World Geography

1.The physical feature of Western Europe where most major cities are found is called A. the plains. B. the glacier.

asked by bree on April 8, 2013
8. ## Social studies

13.the physical feature of western europe where most major cities are found is called A.the plains (MY ANSWER) B.the glacier C.the tundra D.the taiga 14.what made the rhine river one of europes most polluted rivers? A.urbanization B.loess C.industrial

asked by LOVE on March 29, 2016
9. ## Geography

which of the following is an example of a physical feature on earths surface? a) Golden Gate Bridge b) Grand Canyon c) San Diego Zoo d) Sea World Physical features are not man-made. What do you think the answer is?

asked by feroz on March 16, 2007
10. ## self regulated volume control

Hey what's up... does anyone know what does ''self regulated volume control'' mean? I suspect this is what is more commonly called AGC, or automatic gain control. This self regulating amplifer stage compensates for incoming signal strength (stronger input

asked by Piero on August 12, 2005
11. ## astronomy

on a domestic gas cooker the temperture in the hottest part of the flame is about 2200k.if salty eater is spilled in the flame then it becomes yellow-orange.measurements with a spectrometer show the presence of an emission line at 589n. 1) the solar

asked by amy21 on March 3, 2008
12. ## geology

Create a 12- to 15 slide Microsoft® PowerPoint® presentation for your chosen geologic feature. Address the following: · Describe the various geologic events that have occurred in the region around your feature. · Describe the geological features and

asked by sweetbev on April 27, 2012
13. ## chemistry

No clue where to start with this...if someone can just help me setup these problems or assist in any way that would be great. 1. d=2.507 g/1.22 mL = 2.054918033 g mL^-1 explain how both the rules for significant figures and the random error calculation

asked by rich on January 24, 2007
14. ## justice

No clue where to start with this...if someone can just help me setup these problems or assist in any way that would be great. 1. d=2.507 g/1.22 mL = 2.054918033 g mL^-1 explain how both the rules for significant figures and the random error calculation

asked by rich on January 24, 2007
15. ## earth

#37 whenever scientist carefully measure any quantity many times they expect that: a. all the measurements will be exactly the same b. only two of the measurements will be exactly the same c. all but one of the measurements will be exactly the same d. the

asked by ? on January 13, 2013
16. ## SCIENCE :(

What is a Unique physical feature of a Canyon???? Thanks!!! :)

asked by urgh!!! :( on June 11, 2010
17. ## Geography

Is a marsh copse a physical feature?

asked by Stoof on April 5, 2016
18. ## Physics

Could you please check my answers and help me with some? 1. What does it mean to say a physical quantity is conserved? Why is this idea useful? (I don't understand how it is useful) -When a physical quantity is conserved it means that it doesn’t change.

asked by Soly on September 16, 2007
19. ## English (Check)

After reading each passage, write the signal word or words it contains and the type of relationship that each signal word indicates. 1. They entreated us not to be angry any longer, because, even if it was their death, they would take us where we chose. A:

asked by Victoria on February 22, 2016
20. ## 6th geo

a prominent physical feature along the west coast of england is th

asked by &#9829;rebel•stupidity=kathy&#9829; on April 10, 2012
21. ## social studies

Near which type of physical feature was most of the earliest farming villages built?

asked by Kris on August 31, 2010
22. ## social studies

What physical feature is in Africa that is located in the north and separates it from Europe?

asked by t on November 14, 2012
23. ## social studies

What physical feature in Africa is located in the northeast and separates it from Asia?

asked by j on November 14, 2012
24. ## Geography

Near which type of physical geographic feature were the first farming villages built?

asked by Delilah on September 5, 2013
25. ## Social Studies

Near what type of physical feature was most of the earliest farming villages built?

asked by Megan on August 21, 2012
26. ## College Algebra

Problem: In certain signal detection problems (e.g. radar or sonar) the probability of false alarm (FA) (i.e., of saying that a certain signal is present in the data when it actually is not) is given by: ∞ pFA = ∫ _______1_______ x^p/2-1 e-x/2 dx η

asked by Anonymous on November 20, 2010
27. ## physics

The driver of a train traveling at 30 m/s applies the brakes when he passes an amber signal. The next signal is 1.5 km/h down the track and it reaches 75 seconds later. Assuming uniform acceleration, find the velocity of the train at the second signal.

asked by Anonymous on July 20, 2015
28. ## Biology

true or false if an organism randomly develops a feature that gives it a survival advantage, then it will be more likely to survive than other organisms, and will also be more likely to produce offspring which also have this advantageous feature.

asked by Need Help ASAP on May 5, 2013
29. ## Chemistry

I'm going over some post-laboratory questions for Conductivity of Solutions. One of the questions is... From your measurements, what can you say about a) the presence of ionic impurities in tap water? b) the presence of molecular impurities in tap water? I

asked by Jake on February 19, 2009
30. ## SCIENCE HELP ASAP ONLY ONE QUESTION!!!!!!!!!!!!!!!

which of the following is an example of corporate behavior A) a lion hunting a zebra B) Two male peacocks fighting over a female peacock C) A hyena stealing a cheeta's kill D) a bluejay calling to signal the presence of a hawk

asked by LET IT GO on March 12, 2014
31. ## Algebra

Calculate the relative error to the nearest tenth, compared to the actual measurements, given the following swimming pool measurements: Mr. Joe's measurements: 35ft x 17.5ft Actual measurements: 35ft x 22.75ft (A) 0.1 (B) 0.2 (C) 0.3 (D) 0.4 I got choice

asked by Anonymous on May 4, 2008
32. ## health

What is the larynx commonly called?

asked by alley on July 8, 2015
33. ## engineering

Let’s suppose the message x(t) is an analog signal shown in the figure below. a) Draw the block diagrams of the system which converts the analog message signal x(t) to a pulse modulated signal. b) Draw the sampled signal with the sampling frequency

asked by dioptas on June 6, 2013
34. ## Mathematics

A motor car travels 175 km distance from a place A to B,at a uniform speed 70km/hr passes though all ten green traffic signals.Due to heavy traffic it stops for 1 minute at first signal,3 minute at second signal,5 minute at third signal and so on stops for

asked by Sakshi on May 22, 2016
35. ## social studies

Which physical feature covers most of Arabia? empty quarter>>> fertile crescent zagros mountains Persian gulf

asked by ..... on March 8, 2016
36. ## math

A radio station's signal has a radius of 100 miles. If you drive at a constant speed of 40 miles an hour, nonstop, directly across the diameter of the signal, how long can you listen to the station before the signal fades?

asked by dell on June 6, 2013

A radio station's signal has a radius of 100 miles. If you drive at a constant speed of 40 miles an hour, nonstop, directly across the diameter of the signal, how long can you listen to the station before the signal fades?

asked by Lexi on June 26, 2010
38. ## Science

What physical process is being observed using spectroscopic measurements in Beer's Law experiment?

asked by Candice on September 2, 2010
39. ## Biology

Select two signal mechanisms that activate transcription in response to an external signal. Any of these systems ultimately activates a transcription factor. For each of the systems you have selected, trace the route from signal binding to receptor to the

asked by M.C.Filth on October 23, 2011
40. ## history

during the colonial 1580-1776 which physical feature presented the greatest obstacle to colo nists who wanted to move westward

asked by kendra on September 27, 2012
41. ## Social Studies

Which physical feature covers most of Saudi Arabia? the Empty Quarter the Fertile Crescent the Zagros Mountains the Persian Gulf

asked by Unknown on February 25, 2015
42. ## social studies

witch physical feature covers most of arabia? a.the empty quarter b.the fertile crescent c.the zagros mountains d.the persian gulf

asked by Hannah on February 25, 2015
43. ## science help

which of the following is an example of cooperative behavior? A.a lion hunting a zebra B.two male peacock fighting over a female peacock**** C.a hyena stealing a cheetah's kill D.a blue jay calling to signal the presence of a hawk.

asked by Regan on November 10, 2015
44. ## health

Which approach is commonly used to treat eating disorders? A. Electroshock therapy B. Nutritional counseling C. Physical fitness D. None of the above b?

asked by Aya on August 1, 2012
45. ## Social Studies

Which physical feature covers most of arabia? A) The Empty Quarter?** B) The Fertile Crescent? C) The Zagros Mountains? D) The Persian Golf? i think it might be A? but I'm not sure, if you could just check this out that'd be great =)

asked by Kiana on February 16, 2017
46. ## college

Communication channels - physical presence, written-printed, electronic/computer what are the advantages and disadvantages of each?

asked by Gwen on December 8, 2010
47. ## calculus

In electrical engineering, a continuous function like f(t)=sin(t), where t is in seconds, is referred to as an analog signal. To digitize the signal, we sample f(t) every ∆t seconds to form the sequence Sn= f(n∆t). For example, sampling f every 1/10

asked by Sam on March 19, 2017
48. ## Geography

What physical feature blocks access to the Indian subcontinent to its north and northeast? A. the Himalaya Mountains B. the Bay of Bengal C. the Deccan Plateau D. the Thar Desert

asked by can't ban me, can you? on October 8, 2018
49. ## Social Studies

What physical feature blocks access to the Indian subcontinent to its north and northeast? A. the Himalaya Mountains B. the Bay of Bengal C. the Deccan Plateau D. the Thar Desert I think it's A, but I'm not sure.

asked by bob the builder boi on October 9, 2018
50. ## math

Taking the speed of the radio signal as 3×108 m/s, calculate the time taken for a signal to reach a GPS receiver from a GPS satellite at a position 21 000 km distant from the receiver. Assume that the speed of the signal is unchanged over the whole path

51. ## 7th grade science ASAP

1. How many chromosomes do human sex cells have? (1 point) 22 43 46 23 2. The actual genetic makeup of an organism for a particular trait is called the ______. The physical characteristic that trait gives the organisms is called the ______. (1 point)

asked by Delilah on January 17, 2013

1. How many chromosomes do human sex cells have? (1 point) 22 43 46 23 2. The actual genetic makeup of an organism for a particular trait is called the ______. The physical characteristic that trait gives the organisms is called the ______. (1 point)

asked by Delilah on January 17, 2013
53. ## Statistics

A sample of 12 measurements has a mean of 37 and a standard deviation of 4.25. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 37 each. A. Find the mean of the sample of 14

asked by Anonymous on September 4, 2014
54. ## Social Studies

Which physical feature would have the GREATEST impact on Sub-Saharan Africa? A) Sahara Desert B) Kalahari Desert C) Atlas Mountains D) Mount Kilimanjaro

asked by Anonymus on November 14, 2018
55. ## discipline

When Pat talks during math instruction, Mrs. Miller puts Pat's name on the board. If Pat interrupts the lesson again, she will receive a check by her name and lose five minutes of recess. What type of discipline is this called? Is it assertive discipline?

asked by Kayla on January 14, 2007
56. ## English

I find it difficult to check these sentences since the punctuation is missing, the word choice is unclear and they contain grammar mistakes! I really hope you can help me. I think we need to simplify the sentences. 1) Mary Shelley's Frankenstein, unlike

asked by Henry2 on January 2, 2012
57. ## Health

What is the trachea commonly called? A. Voice box B. Vocal cord C. Windflute D. Windpipe A? i don't get this please HELP ME!!!

asked by Martin1162 on March 14, 2016
58. ## Physics

In TV picture, faint, slightly offset ghost images are formed when the signal from the transmitter travels to the receiver both directly and indirectly after reflection from a building or some other large metallic mass. In a 25 inch set, the ghost is about

asked by J on March 31, 2008
59. ## science

Please check these! Physical or Chemical properties? 1. solubility = physical 2. melting point = physical 3. reacts with water to form a gas = physical

asked by Reed on September 13, 2012
60. ## information technology

discuss the following wireless transmittion medium:satillite signal microwave link infrared signal

61. ## History

What physical feature especially attracted European colonists? A.Many offshore islands B.Fertile soil along high mountain cliffs C.Natural harbors along Atlantic Ocean D.Large lakes located along the coastline

asked by M on December 16, 2014
62. ## Criminal Justic

What is commonly called transfer evidence? hairs and fibers heel imprints weapons blood stains

asked by Faye on November 13, 2007
63. ## Physical Education

I have to da a 10 page paper on Integration of health and physical education in curriculum. I need help finding 10 journal articles that are peer-reviewed, current trends and political background. Help please???

asked by LaTarial Williams on February 13, 2014
64. ## physics

A radio receiver is set up on a mast in the middle of a calm lake to track the radio signal from a satellite orbiting the Earth. As the satellite rises above the horizon, the intensity of the signal varies periodically. The intensity is at a maximum when

asked by Anonymous on May 21, 2011
65. ## physics

A radio receiver is set up on a mast in the middle of a calm lake to track the radio signal from a satellite orbiting the Earth. As the satellite rises above the horizon, the intensity of the signal varies periodically. The intensity is at a maximum when

asked by ryan on May 21, 2011
66. ## Physics

A radio receiver is set up on a mast in the middle of a calm lake to track the radio signal from a satellite orbiting the Earth. As the satellite rises above the horizon, the intensity of the signal varies periodically. The intensity is at a maximum when

asked by Anonymous on May 21, 2011
67. ## information technology

discuss the following wireless transmittion medium: 1.satillite signal 2.micro wase link 3.infrared signal

asked by Shaquille on February 23, 2010
68. ## L.A or C.A

Hello everyone! I have a question about feature articles... How is it suppose to look like? Can you find me a feature article on anything so I can see the formate? well thank you! =)

asked by Nick on February 24, 2008
69. ## physics

. A sonar signal is sent from a ship and the signal returns from the bottom 3.65 s later. How deep is the ocean if the speed of sound in water is 1,530 m/s?

asked by Benji on April 4, 2014
70. ## WAN

Provide a hypothetical situation for each signal type that illustrates how it could be, or is being, used in a WAN. In what circumstance, for example, would a company choose to use a satellite signal

asked by Marty on January 31, 2013
71. ## Math

A signal is transmitted over a noisy channel. It is known that the signal will be correctly received with probability 0.797. If 3 copies of the signal are independently sent over this channel, what is the probability that at least one of them is received

asked by Janea on September 14, 2016
72. ## Statistics

A signal is transmitted over a noisy channel. It is known that the signal will be correctly received with probability 0.797. If 3 copies of the signal are independently sent over this channel, what is the probability that at least one of them is received

asked by Janea on September 14, 2016
73. ## statistics

A sample of 12 measurements has a mean of 34 and a standard deviation of 4.5. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 34 each. A. Find the mean of the sample of 14

asked by Anonymous on May 3, 2011
74. ## medical electronics

Autocorrelation matrix of input signal (noise-corrupted signal) x(n), Φxx is [Note: Φd and Φm are autocorrelation matrix of desired signal and noise, respectively] Φd∗Φm Φd+Φm Φd−Φm Φd/Φm

asked by biomedical signal processing on February 12, 2018
75. ## English

Signal Phrase: Read "Too Much Pressure" by Colleen Wenke (564-568). Consider it a model for using signal phrases to introduce quoted material as explained on pages 508-512 of the Bedford Handbook. 1. Copy two good examples from Wenke's essay of signal

asked by Sal on July 3, 2013
76. ## language arts

Need to confirm if the verbs in the sentences are physical or mental actions: 1. However he won only 2 medals --Physical 2. Spitz also teamed with three other Americans in 3 relay races - Physical 3. In total, Spitz won s7 gold medals in a single

asked by cee on March 17, 2014

A sample of 12 measurements has a mean of 24 and a standard deviation of 4.5. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 24 each. Find the standard deviation of the sample of 14

asked by JT on January 25, 2009
78. ## Statistics

A sample of 12 measurements has a mean of 24 and a standard deviation of 4.5. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 24 each. Find the standard deviation of the sample of 14

asked by Nao on January 25, 2009
79. ## statistics

A sample of 12 measurements has a mean of 20 and a standard deviation of 2. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 20 each. Find the standard deviation of the sample of 14

asked by Bob on October 11, 2011
80. ## action potentials

this is in regards to action potentials. they do not affect the membrane potential of neurons. they increase in magnitude as they travel along an axon. they can be measured by using electodes. there is a loss in signal as they travel along an axon. just

asked by sarahinwiss on November 26, 2006
81. ## PreCalc

The decibel (dB) is defined as dB= 10log (P2/P1), where P2 is the power of a particular signal. P1 is the power of some reference signal. In the case of sounds, the reference signal is a sound level that is just barely audible.How many dBs does a sound

asked by jj on October 10, 2010
82. ## Energy Science

___ can convert sound waves to an electrical signal that can be converted to radio waves, microwaves, or light waves. Receiver convert the tramsmission back into electric signal, and the speaker changes the electric signal into a ___ wave

asked by Lucas Parker on January 1, 2010
83. ## Geography (Ms.Sue ) Help

Moving from coastal to interior regions of sub-Saharan Africa, we discover that the dominant physical-geographic feature is  A. many coastal inlets. B. mountainous terrain. C. ascending plateaus. D. lush rainforest. C?

asked by Brooklyn on January 5, 2016
84. ## World Geography

Moving from coastal to interior regions of sub-Saharan Africa, we discover that the dominant physical-geographic feature is A. many coastal inlets. B. lush rainforest. C. ascending plateaus. D. mountainous terrain.

asked by Minh Turley on June 19, 2013
85. ## World Geography

Moving from coastal to interior regions of sub-Saharan Africa, we discover that the dominant physical-geographic feature is A. many coastal inlets. B. lush rainforest. C. ascending plateaus. D. mountainous terrain.

asked by Minh Turley on June 19, 2013
86. ## Geology

What does it mean to discove a popular geographic feature in my region. Could someone give me some examples of what I should be looking for? The question goes on to ask what major rock type does the feature consist of... I'm confused, please help

asked by sam on December 18, 2009

Calculate the wavelength of the signal sent by Q101 assuming that the actual frequency is 101.1 MHz. Determine how long it would take the signal to reach a car 33.4km away from the station. THANK YOU!

asked by Mike Jones on May 23, 2013
88. ## physics

An FM radio station broadcasts its signal at a frequency of 9.15 ×107 hertz. Determine the wavelength of the signal in air. Round your answer to the nearest hundredth of a meter.

asked by ashley -- on April 19, 2011
89. ## Signals and System using matlab

I have a hidden message exists in the wavfile and I need some signal processing to extract the hidden message. The hidden message is the first half of the odd part of this signal. How can I extract the hidden message and listen to it ?? and I should

90. ## physics

A state trooper’s car sends out a radar signal at a frequency of 13.3 GHz. Find the wavelength of this signal. The wave speed is 2.998 × 108 m/s. Answer in units of m

asked by LILY on September 18, 2014
91. ## computer

hi on my computer, i put a background on the desktop. i didn't like that one so i got another background but how do i get rid of the old one. because everytime i log on using my log in name, the picture of the old picture pops up and then my new background

asked by apoorva on March 12, 2007
92. ## science

the neuron that transmit the signal to your foot to kick a soccer ball are called reflexes motor neurons sensory neurons interneurons

asked by noah on September 24, 2014
93. ## science

the neuron that transmit the signal to your foot to kick a soccer ball are called reflexes motor neurons sensory neurons interneurons

asked by noah on September 24, 2014
94. ## Chemistry

Propane gas (C3H8) burns completely in the presence of oxygen gas (O2) to yield carbon dioxide gas (CO2) and water vapor (H2O). Write a balanced equation for this reaction. Assuming that all volume measurements occur at the same temperature and pressure,

asked by O on March 6, 2015
95. ## Chemistry

Propane gas (C3H8) burns completely in the presence of oxygen gas (O2) to yield carbon dioxide gas (CO2) and water vapor (H2O). Write a balanced equation for this reaction. Assuming that all volume measurements occur at the same temperature and pressure,

asked by X on February 20, 2015
96. ## History

What Physical Feature of the New World's Coastline greatly attracted European Colonits A.Offshore islands B.Fertile soil along high moutain cliffs C.Natural harbors along the Atlantic Coast D.Large lakes along the coastline D?

asked by M on December 16, 2014
97. ## English

I have to do a professional business letter to a bank from me a customer there. What i need help in is the letter measurements without a heading. I'm not sure what they are. What i think they are is for the alignment: Left side 1" Top 2" Please help me in

asked by Jasmine07202006 on October 11, 2006
98. ## Health

Characteristics caused by hormones but that do not include development of reproductive organs are called........ A. primary sex Characteristics B. secondary sex characteristics C. physical Characteristics D. body Characteristics The many physical changes

asked by Amber on August 25, 2014
99. ## Geology

I am in need of help with my final project in Geology. I have to create a 12-15slide powerpoint presentation on Factors and Forces of Geological Features. I have the final rubric Final Rubric: |Factors and Forces of Geological Features Objective of

asked by Maren on January 29, 2011
100. ## math

A radio station broadcasts a signal over an area with radius of 50 miles. The station can relay the signal and broadcast over an area with a radius of 75 miles. How much greater is the area of broadcast region when the signal is relayed? Round your answer

asked by Tim on December 31, 2015