# Questions tagged [instrument]

A measurement instrument is a device used to sample physical observations. Examples include pressure sensors, thermocouples, etc.

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### Why is my pyrgeometer calibrated as if it has $a >1$ emissivity?

I've acquired an SL-510-SS upward-looking pyrgeometer. In the manual it gives the formula for how to compute the downwelling infrared it picks up: Clearly the $k_2$ coefficient is the emissivity of ...
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### An instrument for sensitive time interval measurements?

I had the idea to do an experiment at home that would let me calculate the air resistance. $F_{net} = m.a = m.g - f_k$ (kinetic friction), in the case of free fall, so I thought I’d drop an object of ...
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### Sound radiated by wind instrument

My understanding of how a wind instrument (modeled as a tube open on both ends) works is as follows: Person blows into one of the open ends to create pressure waves. These pressure waves are ...
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### What is meant by precision of a measuring instrument?

I came across many definitions of the precision of a measuring instrument such as, "a precise measuring tool is one that can measure values in very small increments" and "The precision ...
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1 vote
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### Why to use the Callendar equation instead of the temperature coefficient differential equation?

The temperature coefficient differential law gives an equation for the temperature coefficient $\alpha$, which describes the relative change of a physical property $R$ that is associated with a given ...
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### What is heard when a tuning fork is struck?

When a tuning fork is struck I hear two tones. From a distance I can hear a high octave frequency of the pitch of the tuning fork. Though, if I listen to it closely (closer to my ears), I also hear a ...
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1 vote
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### Is the lens image, a combination of diffraction patterns?

As I was reading through Luigi Picasso's Lectures in QM, I came across this paragraph where he explains the reason behind the resolution power of the optical instruments. He writes: Let us now ...
61 views

When building electronics to measure usually it is asked what the bandwidth of the signal is and what is the frequency range usually done to limit noise bandwidth and thus have more SNR. To me it ...
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### How should I esteem the measurement error using an instrument with high precision and low accuracy?

I was performing an experiment about the Beer–Lambert law using a luxmeter I bought online. In the user manual it's stated it has "$Accuracy: \pm\,3\%\,reading\pm\,8\,digits$". During the ...
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### Why is the bias instability read from my Allan Deviation plot different than my simulation input? [closed]

I have simulated a gyroscope at rest with angular random walk and bias instability, following the mathworks IMU simulation model found here. In conjunction with that simulation model, I am plotting ...
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### What is the meaning of "Dual Accuracy" on this datasheet?

I'm trying to determine the uncertainty in some of my measurements, and one of the variables I measure is temperature, using a Tenma 72-7715 thermometer. I looked up the datasheet to find the ...
1 vote
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### The sun's neutrinos and the brain [closed]

Is it possible for the sun's neutrinos to be detectable biologicaly . Or what is the simplest way for a experimenter to detect neutrinos externally?
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### Difference between BATT and Voltage on multimeter

My digital multimeter (the one in the picture) has a function called "BATT", which, according to the manual, is used to read the voltage of batteries. I noticed that it gives different ...
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### What physical state of a wound string corresponds to a 'tuned' string?

Many instruments can be strung with strings comprised of a solid core and wound with another metal wire, e.g. the viola. I was wondering about the physical state of wound strings when they are 'in ...
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### Instrument limitations and capabilities [closed]

What do we mean by instrument? Explain the limitation and capability of an instrument.
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### How is the formula $R=l^2/6h+h/2$ for calculation radius of curvature of a spherical surface is derived? [closed]

The problem with the derivation is that in one figure the point M is taken the bisector of AB while in the second one it is completely out of the line AB. So for AM.MB=OM.MZ to be true the chords AB ...
1 vote
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### Why doesn't the thermometer go back to ambient temperature after I take my temperature?

These past days I had a fever and I have taken my temperature many times with the thermometer in the photo. I think this is just like a mercury thermometer, even if it's a newer one that does not ...
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### What is the difference between MOKE hysteresis loop and VSM Hysteresis loop?

I need to understand what is the difference between Magneto-optical Kerr effect (MOKE) hysteresis loop and vibrating sample magnetometer (VSM) hysteresis loop? And the use of each one of them?
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### Pumping laser for Ti:Sapphire laser

I now own Tsunami Ti: Sapphire laser from Spectra-Physics. This laser is an ultrafast laser. Now, this is pumped by Millenia CW green laser. Apart from the output coupler problem, I am considering ...
53 views

### Measuring temperature at submicron resolution

Do we have any microscopic technique/protocol to measure temperature at sub-micron resolution?
51 views

### Numerical Problems Based On Vernier Callipers [duplicate]

I watched a video on Vernier Calipers which gave me an understanding of how it works and how to read a Vernier Caliper. I also tried the GeoGebra simulation. But I am not able to understand the ...
482 views

### Changes to a thermometer that would require the spacing of the division to be larger

A mercury-in-glass thermometer having a larger bulb, a narrower capillary tube and more liquid will need to have a larger space between the divisions for an accurate reading compared to other ...
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### What is the difference between a photon's phase and polarization?

When talking about a photon emitted by a laser device, what is the difference between phase and polarization? Is it redundant to specify both the polarization and the wavefunction's phase? Does a ...
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### How to measure wind speed non-accoustically without moving parts? [closed]

I heard that there are ways to measure wind speed independent of the direction other than the usual anemometer or acoustic Doppler profilers, with a setup without any moving parts. Could somebody ...
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### What is the name for the instrument to measure radiation consisting mainly out of a glass ball?

I remember vaguely a measurement instrument to protocol probably solar irradiance. The instrument mainly consisted out of a glass sphere and if I recall correctly, the sun was "writing" ...
• 115
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### Is it possible to visualize water vapour with a low-cost instrument or setup in a lab? [closed]

Would infrared or laser be of any help? In a lab setting.
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### Zero Error of Screw Gauge

Consider a screw gauge of 50 divisions on the circular scale. Till now I have used the following method to account for zero error in it. If $x^{th}$ division on the circular scale coincides with the ...
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### Is there an instrument which can show the magnetic field in a region?

I know that an instrument called magnetometer exists. But it can only measure the magnetic field at a given point. I wonder if there exist, or is it possible to build a device which would be able to ...
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### What is the smallest acceleration ever measured? [closed]

I'm having an argument (discussion) with a referee. I claim that the effects of expansion can be seen in local dynamics. That the orbit of Saturn is affected infinitesimally by the expansion of ...
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### How is it possible to do spectral analysis of a light source?

I have a big book published many years ago by NASA which is page after page of numbers, the numbers being the irradiance of the sun at particular wavelengths. I wonder how such a book could be ...
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### Is it possible to consider the oscilloscope as an essential instrument?

I recognize that the oscilloscope is a very useful instrument. But I would like to know what are the reasons why the oscilloscope is such a useful instrument in day-to-day scientific work. I would ...
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### How does a Bourdon tube maintain constant volume?

I would like to understand why a Bourdon tube works, the working principle is described on wikipedia as: The Bourdon pressure gauge uses the principle that a flattened tube tends to straighten or ...
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### What will happen if we try to take a voltage reading by keeping it in current mode in a multimeter?

There are different modes present in a multimeter. one is the current mode and voltage mode for their respective measurements. what will happen if one try to take a voltage reading by keeping it in ...
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### When does the sensitivity of tangent galvanometer approaches a max value?

The image shows the approach of a few saying that the sensitivity is maximum if the deflection approaches zero. The white portion is a snap of a reference book which says the sensitivity is maximum if ...
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### Identifying Physics Equipment

We are clearing out some old cupboards at school in our science department and have come across three different sets of physics equipment with no labels or instructions. Please could people kindly ...
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### Is there an instrument that measures temperature (dynamic reading) at high irradiation doses?

I would like to measure the temperature in industrial gamma irradiation bunker. I know thermocouples are often used, but they only give max temperature reading, and I would like to have a dynamic ...
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1 vote
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### Accurate method or instrument to measure density of shaving cream foam or whipped cream foam?

I am currently filling a "standard" stainless steel cup of known volume with foam and then I weigh it. Then I calculate density. This method is pretty messy and I have to be careful about how I fill ...
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1 vote
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### How can the apex angle of a Fresnel biprism be equal to $180^\circ$?

I am learning about Fresnel biprism. I wanted to know about biprism, and found out on the internet that it is a triangular prism with apex angle $180^\circ$. But I am unable to interpret $180^\circ$. ...
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### Why do hot-wire instruments have a non-linear scale?

Hot-wire instruments are used to measure rms voltage or rms current in AC circuits. The construction of a hot-wire instrument is shown in the following diagram: Image source: Hitzdrahtmesswerk (Hot ...
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### How does ultrasound imaging localize points in the $x$-$y$ plane?

Lots of sources describe how ultrasound imaging uses the time differences between wave emission and reception to calculate distances to points in the body. This makes sense for how localization works ...
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### Probability that the Hubble space telescope hit by Meteoroids

What if Hubble Space Telescope or International Space State hit by micrometeoroid or meteoroid? Asking because these objects are moving at a very high velocity.
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### How to decide the arrangement of an individual telescope in an astronomical interferometer?

Let's take the example of GMRT radio telescope, where individual telescopes are arranged in Y pattern. Please explain in detail.
1 vote
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### How the diffraction occurs in cassegrain telescope?

I know about the diffraction limit of a telescope. But please explain through diagram how diffraction occurs in Cassegrain telescope which has both primary as well as a secondary reflector.
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### Why bulk of HPGe detectors is doped?

When I am looking at schematic diagrams of HPGe gamma spectrometer detectors (like this Ortec GLP one), it is often mentioned that bulk of Ge is doped. In this example - P-type doped. Is there a ...
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### Does a pipe hit at the top behave like an open-open system or an open-closed system?

I'm making an instrument from an open-ended tube that produces sound when the top (opening) is struck. To find the lengths corresponding to pitches, I used $$V = \lambda f \tag{1} \label{1}$$ and ...
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### What is spectral redshift resolution of observationally detected damped Lyman Alpha clouds?

What is the spectral resolution, $\Delta z,$ when detecting damped Lyman alpha systems at different epochs, $z \sim 0-3,$ through current and/or future observational instruments? And is this redshift ...
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### Why is Fresnel Biprism a "Bi-" prism?

Why is the Fresnel Biprism made of two separate prisms joined together at their bases? Why not use a monoprism, a single prism having the same overall geometric and optical properties as that of the ...
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1 vote
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### Why is there no standardization of indentation hardness measurements? [closed]

The last hundred years have seen a great degree of standardization of units, and the expression of units of measurement in standardized, instrument-agnostic, objective terms. So I wonder why this ...
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45 views