two charges + 2.6 uc and -5.4uc experience an attractive force of 6.5mN. What is the separation between the charges?

The photon energies used in different types of medical x-ray imaging vary widely, depending upon the application. Single dental

pav-90 [236]

A) $5.0\cdot 10^{-11} m$

The energy of an x-ray photon used for single dental x-rays is

$E=25 keV = 25,000 eV \cdot (1.6\cdot 10^{-19} J/eV)=4\cdot 10^{-15} J$

The energy of a photon is related to its wavelength by the equation

$E=\frac{hc}{\lambda}$

where

$h=6.63\cdot 10^{-34}Js$ is the Planck constant

$c=3\cdot 10^8 m/s$ is the speed of light

$\lambda$ is the wavelength

Re-arranging the equation for the wavelength, we find

$\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{4\cdot 10^{-15}J}=5.0\cdot 10^{-11} m$

B) $2.0\cdot 10^{-11} m$

The energy of an x-ray photon used in microtomography is 2.5 times greater than the energy of the photon used in part A), so its energy is

$E=2.5 \cdot (4\cdot 10^{-15}J)=1\cdot 10^{-14} J$

And so, by using the same formula we used in part A), we can calculate the corresponding wavelength:

$\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{1\cdot 10^{-14}J}=2.0\cdot 10^{-11} m$

4 0

3 years ago

A thin partition divides a thermally insulated vessel into a lower compartment of volume V and an upper compartment of volume 2V

Anni [7]

Answer:

1.89mol

Explanation:

The entropy change during free expansion is express as

$S_{f}-S_{i}=nRln(\frac{V_{F}}{V_{I}})\\$

Where S is the entropy of the system,

n is the amount of mole

R is the gas constant = 8.314 and

V is the volume occupied at the initial and final stage

since the process is n adiabatic free expansion, the entropy of the system is constant. Hence we can re-write the equation as

$S=nRln(\frac{V_{F}}{V_{I}})\\$

where the $V_{i}=v\\$ and $V_{f}=2v+v=3v\\$

$S=17.28J/k\\$ and

$R=8.314\\$

Now if we substitute in values we arrive at

$17.28=(8.314)n*ln(\frac{3v}{v} )\\17.28=(8.314)n*ln(3 )\\17.28=(8.314)n*1.0986\\n=\frac{17.28}{8.314*1.0989}\\n=1.89 mole\\$

6 0

3 years ago

A girl with a mass of 27 kg is playing on a swing. There are three main forces

N76 [4]

The tension in the swing's chain at the bottom of the swing is 178.35 N.

The given parameters:

Mass of the girl, m = 27 kg
Speed of the girl, v = 3 m/s
Radius of the circle, r = 4 m

The tension in the swing's chain at the bottom of the swing is calculated as follows;

$T = mg + ma_c\\\\ T= mg + \frac{mv^2}{r} \\\\T = (12 \times 9.8) + (\frac{27 \times 3^2}{4} )\\\\T = 117.6 \ N \ + \ 60.75 \ N\\\\T = 178.35 \ N$

Thus, the tension in the swing's chain at the bottom of the swing is 178.35 N.

Learn more about tension in vertical circle here: brainly.com/question/19904705

3 0

2 years ago

In order for an external force to do work on a system, Question 9 options: a) there must be a component of the force perpendicul

zepelin [54]

Answer:

b) there must be a component of force parallel to the motion of the object.

Explanation:

We know that work done on a body by an external force is calculated by the formula given below:

W = F.d = Fd Cos θ

where,

W = Work Done by the force on the body

F = Magnitude of force

d = displacement of the body

θ = The angle between the direction of motion of the body and the force applied

It is clear from the formula of the work done, that "F Cosθ" represents the component of the force, that is acting in the direction of motion of the object or parallel to the direction of motion of the object. So, if there is no component of force parallel to motion of object, then this factor will become zero. As a result, the work done will also be zero.

Therefore, the correct option will be:

b) <u>there must be a component of force parallel to the motion of object.</u>

6 0

3 years ago

Explain why your senses would lead you to believe that the Earth is center of the universe

ASHA 777 [7]

<u>Answer:</u>

This is due to the apparent movement of the celestial bodies, seen from an observer centered on the Earth. If we did not have knowledge of the advances of science and the latest discoveries, we would think that the Earth is the center of the universe.

For example, for an observer on Earth as a reference system, the Sun moves every day from east to west, as do the planets and all the stars that we observe at night, which leads the observer to believe that those in motion are these bodies outside in the sky while the earth is still and fixed in the universe.

Keep in mind that this theory of geocentrism was widely accepted for a long time in antiquity, until the astronomer Nicolaus Copernicus proposed a completely different and opposite idea, heliocentrism (universe centered on the Sun).

However, at present it is known and accepted that the universe has no center, that the Earth revolves around the Sun and that in reality all the bodies of the universe are in movement.

5 0

3 years ago