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4 years ago

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The Coulomb force between two charges q1 and q2 at separation r in air is F. If half of the separation is filled with medium of

dielectric constant 9, what will be the value of new coulomb force?

1 answer:

vodomira [7]4 years ago

3 0

Answer:

The new Coulomb force is q₁q₂/9πε₀r²

Explanation

The coulomb force between the two charges q₁ and q₂ at a distance r in air is given by F = q₁q₂/4πε₀r².

Now, let us assume the material of dielectric constant κ = 9 is placed between them on the side of the q₁ charge. The value of its effective charge is now q₃ = q₁/κ at a distance of d = r/2 from the q₂ charge.

Since we have air between q₂ and q₃, the coulomb force between them is

F' = q₂q₃/4πε₀d²

= q₂(q₁/κ)/4πε₀(r/2)²

= 4q₂q₁/κ4πε₀r²

= 4/κ(q₂q₁/4πε₀r²)

= 4/9 × (q₂q₁/4πε₀r²)

= q₁q₂/9πε₀r²

So, the new Coulomb force is q₁q₂/9πε₀r²

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Energy can be changed from one form to another. Which terms can be used to describe these changes? Select all that apply.

aliya0001 [1]

Energy is the capacity to do work. Energy exists in various forms in the entire universe.

It may be light,sound,electric,magnetic,kinetic,potential,thermal energy etc.

As per the law of conservation of energy, it is neither created not destroyed. It can change from one form to another form.The total energy of the universe is always constant.

The process in which energy will change from one form to another form is called energy conversion.

There is also another terminology for energy conversion called energy transformation.

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Hence the correct answer to this question will be conversion and transformation

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4 years ago

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What do you think happened to the energy you transferred to the notebook when you pushed it?

xeze [42]

Answer:

It got transferred to kinetic energy

Explanation:

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3 years ago

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A student is experimenting with some insulated copper wire and a power supply. She winds a single layer of the wire on a tube wi

OverLord2011 [107]

Answer:

$P=214.7187\,W$

Explanation:

Given that:

Diameter of the solenoid, $D=10\,cm=0.1\,m$

length of the solenoid, $L=90\,cm=0.9\,m$

diameter of the wire, $d=0.1\,cm=10^{-3}\,m$

magnetic field at the center of the solenoid, $B=7.4\times 10^{-3}\,T$

<u>Now we need the no. of turns incorporated in the length of 90 cm:</u>

$N=\frac{Length\,\,of\,\,solenoid}{diameter\,\,of\,\, wire}$

$N=\frac{L}{d}$

$N=\frac{0.9}{10^{-3}}$

$N=900\,\,turns$

For solenoids we have:

$B=\mu.n.I$ ...............................(1)

where:

$\mu=$ permeability of the medium

n = no. of turns per unit length

I = current in the coil

So,

$n=\frac{900}{0.9}$

$n=1000\,turns\,.\,m^{-1}$

Now putting the respective values in the eq. (1)

$7.4\times 10^{-3}=4\pi\times10^{-7}\times 1000\times I$

$I=5.8887\,A$

For copper we have resistivity:

$\rho=1.72\times 10^{-8}\, \Omega.m$

We know that resistance is given by:

$R=\rho.\frac{l}{a}$ .....................................(2)

where:

l = length of the conducting wire

a = cross sectional area of the conducting wire

<u>Now we need the length (l) of the wire:</u>

Circumference of the solenoid,

$C=\pi.D$

$C=0.1\pi\,m$

$\therefore l=C\times N$

$l=90\pi\,m$

&

<u>Cross-sectional area of wire:</u>

$a=\pi.\frac{d^2}{4}$

$a=\pi. \frac{(10^{-3})^2}{4}\,m^2$

<u>Resistance from eq. (2):</u>

$R=1.72\times 10^{-8}\times \frac{90\pi}{\pi. \frac{(10^{-3})^2}{4}}$

$R=6.192 \,\Omega$

For power we have:

$P=I^2.R$

$P=5.8887^2 \times 6.192$

$P=214.7187\,W$

6 0

3 years ago

The take-up reel of a cassette tape has a radius of 2.5 cm. Find the length of the tape that passes around the reel in 7.1 s whe

Jet001 [13]

Answer:

s = 0.337 m

Explanation:

First, we will find the angular displacement of the reel:

$\theta = \omega t$

where,

θ = angular displacement = ?

ω = angular speed = 1.9 rad/s

t = time taken = 7.1 s

Therefore,

θ = (1.9\ rad/s)(7.1 s)

θ = 13.5 rad

Now, we will find out the length of tape:

s = rθ

where,

s = length of tape = ?

r = radius of reel = 2.5 cm = 0.025 m

Therefore,

s = (0.025 m)(13.5 rad)

<u>s = 0.337 m</u>

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3 years ago

1) How does the frequency of sound affect the speed of sound?

Travka [436]

Changing frequency of sound does not change the speed of the sound.

Explanation:

Speed of the sound gets altered when the sound travels from one medium to another.
Change in frequency does not affect the speed of the sound and speed is affected by the properties of the medium through which it travels.
Therefore, to change the speed of the sound, the properties of the medium needs to be changed.

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3 years ago