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What Is Rho In Physics

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Doubling The Area Of A Conductor

What is the moment of inertia of a solid of density rho and radius R about its diameter ? | 11 |…

Here by connecting the two conductors together in a parallel combination, we have effectively doubled the total area giving 2A, while the conductors length, L remains the same as the original single conductor. But as well as doubling the area, by connecting the two conductors together in parallel we have effectively halved the total resistance of the conductor, giving 1/2R as now each half of the current flows through each conductor branch.

Thus the resistance of the conductor is inversely proportional to its area, that is: R 1/ A, or R 1/A. In other words, we would expect the electrical resistance of a conductor to be proportionally less the greater is its cross-sectional area.

Also by doubling the area and therefore halving the total resistance of the conductor branch , for the same current, i to flow through the parallel conductor branch as before we only need half the applied voltage as now I = /.

So hopefully we can see that the resistance of a conductor is directly proportional to the length of the conductor, that is: R L, and inversely proportional to its area , R 1/A. Thus we can correctly say that resistance is:

We Know That $r=$ But How Do You Define L And A Area Of Cross Section

How do we define area of cross section of a conductor for resistance of a metal piece.

When you a wire which is generally cylindrical you have a length of it. Its area of cross section is a circle whose plane is perpendicular to the length of cylinder at any point.

But what if it take a very irregular shape which we would call as a piece not wire. How can i calculate its length and area of cross-section after taking any two point om its surface as end points.

Edit:Think of a metal piece which is irregular in shape with no flat surface and take two points A and B on it which are not the farthest point on it.

  • $\begingroup$The formula applies to conducting wires. Have you ever seen a conducting wire that was not composed of one or more cylindrical conductors, and whose resistance is given by $R=\frac $, where $n$ is the number of wire strands in the conductor and $r$ is the radius of each individual conductor?$\endgroup$Dec 25, 2021 at 3:48
  • $\begingroup$Maybe this is helpful$\endgroup$Dec 25, 2021 at 11:59
  • 1

For the formula to work, the conductor must be a general cylinder. That is, its cross section must be the same at all points along its length.

Then the cross-sectional area is the same no matter which location along the length you choose to measure it at.

The cross sectional area is simply the actual cross-sectional area, regardless of how complex the shape of the cross-section is.

Consider an object with an arbitrary cross sectional area $A$ as shown below.

Electrical Resistance As A Function Of Conductivity

Then we can say that conductivity is the efficiency by which a conductor passes an electric current or signal without resistive loss. Therefore a material or conductor that has a high conductivity will have a low resistivity, and vice versa, since 1 siemens equals 1-1. So copper which is a good conductor of electric current, has a conductivity of 58.14 x 106 siemens per metre.

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What Does Rho Mean In Chemistry

Definition of Value Rho Value

A measure of the susceptibility to the influence of substitute groups on the rate constant or equilibrium constant of a particular organic reaction involving a family of related substrates.

How do you write rho?

How do you make rho?

In polytonic orthography, a rho at the beginning of a word is written with a rough-breathing, equivalent to h , and a double rho within a word is written with a smooth breathing over the first rho and a rough breathing over the second .

What is rho Brainly? is defined as the mass of the fluid over an infinitesimal volume. Density is expressed in the British Gravitational system as slugs/ft3, and in the SI system kg/m3. Explanation: laminiaduo7 and 2 more users found this answer helpful.

What Is Electrical Resistance Measured In

A physical quantity `rho` is calculated by using the formula `rho =(1 ...

The SI unit of electrical resistance is measured in ohm, and mathematically it is represented by . The unit ohm is named after German physicist and mathematician Georg Simon Ohm.

In the SI system, an ohm is equal to 1 volt per ampere. Thus,

For details on Distance and Displacement, refer to the linked article.

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How Do You Write Rho

0:471:58How to Write Density Symbol in Word | Rho Symbol – YouTubeYouTubeStart of suggested clipEnd of suggested clipIn the next method. Go up to the insert. Option click on equation. Type backslash and type rhoMoreIn the next method. Go up to the insert. Option click on equation. Type backslash and type rho spacebar to type row symbol in word now if you don’t want to do anything like this go again to insert.

Doubling The Length Of A Conductor

Here by connecting the two conductors together in a series combination, that is end to end, we have effectively doubled the total length of the conductor , while the cross-sectional area, A remains exactly the same as before. But as well as doubling the length, we have also doubled the total resistance of the conductor, giving 2R as: 1R + 1R = 2R.

Therefore we can see that the resistance of the conductor is proportional to its length, that is: R L. In other words, we would expect the electrical resistance of a conductor to be proportionally greater the longer it is.

Note also that by doubling the length and therefore the resistance of the conductor , to force the same current, i to flow through the conductor as before, we need to double the applied voltage as now I = /. Next suppose we connect the two identical conductors together in parallel combination as shown.

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What Is Rho Type

  • RHo immune globulin is a sterilized solution made from human blood. Rh is a substance that most people have in their blood but some people don’t . A person who is Rh negative can be exposed to Rh positive blood through a mismatched blood transfusion or during pregnancy when the baby has the opposite blood type.

What Is Meant By ##\rho: ##

What is the radius of a planet of density rho if at its surface escape velocity of a body is v. …
  • A

Delta2 said:Usually density is a scalar

Ibix said:Yes, but ##\rho_## has nothing to do with density – see how it’s defined in equation 3 in the paper.


Most likely ##\rho## is the density of the “electron continuum fluid”

Ibix said:No – check the units. It’s a component of the resistivity tensor.

Delta2 said:Hmmm, maybe you are right


Normally it should be $$\rho_=\frac$$Usually density is a scalar, at least that’s how I know it when studying most of physics.


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Pressure Due To Fluid Column

Pressure due to a fluid column = height of column X density of the fluid X gravitational field strength .

$$p = \rho g h$$

In a fluid, if two points are separated by a vertical height, their difference in pressure is:

$$\Delta p = \rho g \Delta h$$

From the formula, $p = \rho g h$, we can see that the pressure depends on the depth and density of the liquid and NOT on the cross-sectional area or volume of the liquid. Hence, the water pressure at the bottom of the container in the figure above will be the same throughout the container as the water level is the same! The shape of the container does NOT matter in the computation of the water pressure!

What Is Rho In Physics


Resistivity, commonly symbolized by the Greek letter rho, , is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area A, and divided by its length l = RA/l. The unit of resistance is the ohm


Rho is Symbolized p. Quantitatinely equal to the resistance R of a specimen such as a wire, multiplied by it’s cross-Sectional area A, and divided by the length l P=RA/l.The unit of resistance is the ohm

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How Is F Ma Derived

Are impulse and force the same thing? Force is applied to a body for a longer duration, normally more than a second. Impulse is a force that acts on a body for a short period of time.

What is impulse and its SI unit?

In classical mechanics, impulse is the integral of a force, F, over the time interval, t, for which it acts. The SI unit of impulse is the newton second , and the dimensionally equivalent unit of momentum is the kilogram meter per second .

Rho Calculation And Rho In Practice

A closed rectangular vessel completely filled with a liquid of density ...

The exact formula for rho is complicated. But it is calculated as the first derivative of the option’s value with respect to the risk-free rate. Rho measures the expected change in an option’s price for a 1 percent change in a U.S. Treasury bill‘s risk-free rate.

For example, assume that a is priced at $4 and has a rho of 0.25. If the risk-free rate rises 1 percent, say from 3 percent to 4 percent, the value of the call option would rise from $4 to $4.25.

Assume that put option is priced at $9 and has a rho of -0.35. If interest rates were to decrease from 5 percent to 4 percent, then the price of this put option would increase from $9 to $9.35. In this same scenario, assuming the call option mentioned above, its price would decrease from $4 to $3.75.

Rho is larger for options that are in-the-money and decrease steadily as the option changes to become out-of-the-money. Also, rho increases as the time to expiration increases. Long-term equity anticipation securities , which are options that generally have expiration dates that are greater than one year away, are far more sensitive to changes in the risk-free rate and, thus, have larger rho than shorter-term options.

Though rho is a primary input in the BlackâScholes options-pricing model, a change in interest rates generally has a minor overall impact on the pricing of options. Because of this, rho is usually considered to be the least important of all the option Greeks.

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Temperature Dependence Of Resistance

At higher temperature, the number of free electrons in a conductor increases and resistance is dependent on it. The below equation represents its dependency


\ = resistance of the conductor at 0 °C

\= resistance of the conductor at T °C

= temperature coefficient of the resistance

This equation is valid for T 300 °C

Limitation Of Ohms Law

Ohms law is not a universal law-

  • As this law is valid for a large class of materials but still there do exist materials where ohms law is not valid
  • Ohms law is not valid on unilateral elements like diodes, transistors etc.
  • Even ohms laws do not show constant results between V and I over a long time on elements with non-linear parameters like capacitance, resistance etc.

    To get the details on Nuclear Physics, candidates can visit the linked article.

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    What Does Rho Represent

    • The analysis will result in a correlation coefficient and a p-value. Rho values range from -1 to 1. A negative value of r indicates that the variables are inversely related, or when one variable increases, the other decreases. On the other hand, positive values indicate that when one variable increases, so does the other.

    Kleingordon And Dirac Equations

    rho-T equation of a gas in adiabatic process is given by | 11 | CURRENT ELECTRICITY | PHYSICS | …

    Attempts to combine quantum physics with special relativity began with building relativistic wave equations from the relativistic energymomentum relation

    This has again the form of the Schrödinger equation, with the time derivative of the wave function being given by a Hamiltonian operator acting upon the wave function. Including influences upon the particle requires modifying the Hamiltonian operator. For example, the Dirac Hamiltonian for a particle of mass m and electric charge q in an electromagnetic field is:

    For the KleinGordon equation, the general form of the Schrödinger equation is inconvenient to use, and in practice the Hamiltonian is not expressed in an analogous way to the Dirac Hamiltonian. The equations for relativistic quantum fields, of which the KleinGordon and Dirac equations are two examples, can be obtained in other ways, such as starting from a Lagrangian density and using the EulerLagrange equations for fields, or using the representation theory of the Lorentz group in which certain representations can be used to fix the equation for a free particle of given spin .

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    Example : Calculating Resistor Diameter: A Headlight Filament

    A car headlight filament is made of tungsten and has a cold resistance of \boldsymbol. If the filament is a cylinder 4.00 cm long , what is its diameter?


    We can rearrange the equation \boldsymbol} to find the cross-sectional area \boldsymbol of the filament from the given information. Then its diameter can be found by assuming it has a circular cross-section.


    The cross-sectional area, found by rearranging the expression for the resistance of a cylinder given in \boldsymbol}, is

    Substituting the given values, and taking \boldsymbol from Table 1, yields

    The area of a circle is related to its diameter \boldsymbol by

    Solving for the diameter \boldsymbol, and substituting the value found for \boldsymbol, gives


    The diameter is just under a tenth of a millimeter. It is quoted to only two digits, because \boldsymbol is known to only two digits.

    Rho Symbol In Greek Alphabet

    Rho is the 17th letter of the Greek alphabet. In Greek numerals, it has a value of 100. The letter rho came from the Phoenician letter r, meaning head. The Phoenicians changed the Egyptian Ro and renamed it. But the ancient Greeks didnt make any changes, just renamed it Rho. The lowercase rho is used in economics, mathematics, ecology, molecular biology, computer programming and statistics.

    The Greek letter rho is used to stand for “density”, “resistivity”, in physics. It is also used in “a rho meson” which is a short-lived hadronic particle in particle physics. In mathematics, this greek symbol indicates Dickman’s function, the plastic number, the prime constant, etc. The letter rho stands for Spearman’s rho in statistics, the population damping ratio in ecology, the Rho family of GTPases and the Rho protein in molecular biology. You can also notice that the letter rho is used in The Chi-Rho symbol that is one of the earliest forms of Christogram.

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    What Is Resistivity/ Specific Resistance

    • The constant of proportionality while calculating the resistance of the conductor that depends on the nature of the material is termed as the resistivity of the material. It is denoted by rho .
    • The SI unit of resistivity is -m
    • The specific resistance of a material is defined as the resistance of unit length and unit cross-sectional area of the material of the conductor. It is the intrinsic property of a substance and differs from different materials.

    Practical Implications Of Resistivity

    How do I align these equations?

    The resistivity of materials is important as it enables the right materials to be used in the right places in electrical and electronic components.

    Materials used as conductors, for example in electrical and general connecting wire need to be able to have a low level of resistivity. This means that for a given cross sectional area, the resistance of the wire will be low. Selecting the right material depends on knowing its properties, one of which is its resistivity.

    As an example, copper is a good conductor as it provides a low level of resistivity, its cost is not too high, and it also provides other physical characteristics that are useful in many electrical and electronic applications. The resistivity of copper is around 1.7 x 10-8 ohm metre , although figures will vary slightly according to the grade of the copper

    Materials like copper and even aluminium provide low levels of resistivity and this makes them ideal for use as electrical wires and cables – copper often being the favourite. Silver and gold have much low resistivity values, but as they are considerably more expensive, they are not widely used. However, silver is sometimes used to plate wires where its low resistivity is essential, and gold flashing is used for the mating surfaces of many electronic connectors to ensure the best contacts. Gold is also good for electrical connectors as it does not tarnish or oxidise like other metals.

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    How Do You Find Initial Velocity With Only Time

    What does H mean in physics? Planck’s constant, , fundamental physical constant characteristic of the mathematical formulations of quantum mechanics, which describes the behavior of particles and waves on the atomic scale, including the particle aspect of light.

    Secondly What does the P stand for in P MV? P = MV momentum equals the mass of an object times its velocity .

    Example : Calculating Resistance: Hot

    Although caution must be used in applying \boldsymbol and \boldsymbol for temperature changes greater than 100ºC, for tungsten the equations work reasonably well for very large temperature changes. What, then, is the resistance of the tungsten filament in the previous example if its temperature is increased from room temperature to a typical operating temperature of 2850ºC?


    This is a straightforward application of \boldsymbol, since the original resistance of the filament was given to be \boldsymbol, and the temperature change is \boldsymbol \textbf}.


    The hot resistance \boldsymbol is obtained by entering known values into the above equation:


    Figure 4.

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