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3 years ago

If the needle in the galvanometer is going up, what can you conclude about the motion of the magnet in the diagram?

Physics

2 answers:

Jet001 [13]3 years ago

4 0

Answer:

t is not moving.

It must be moving left.

It must be moving right.

It is being moved in an unknown direction

Answer is: It must be moving right

Explanation:

Papessa [141]3 years ago

4 0

I just took the test, the correct answer is "It must be moving left."

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Four electrons and one proton are at rest, all at an approximate infiitne distance away from each other. This original arrangmen

murzikaleks [220]

Answer:

a) W = 1.63 10⁻²⁸ J, b) W = 1.407 10⁻²⁷ J, c) W = 1.68 10⁻²⁸ J,

d) W = - 4.93 10⁻²⁸ J

Explanation:

a) In this problem we have an electron at the origin, work is requested to carry another electron from infinity to the point x₂ = 0, y₂ = 2.00m

If we use the law of conservation of energy, work is the change in energy of the system

W = ΔU = U_∞ -U

the potential energy for point charges is

U =k $\sum \frac{q_i q_j}{r_{ij} }$

in this case we only have two particles

U = k $\frac{q_1q_2}{r_{12} }$

the distance is

r₁₂ = $\sqrt{(x_2-x_1)^2 + ( y_2-y_1)^2 }$

r₁₂ = $\sqrt{ 0 + ( 2-0)^2}$ Ra 0 + (2-0)

r₁₂ = √2= 1.4142 m

we substitute

W = k \sum \frac{q_i q_j}{r_{ij} }

let's calculate

W = $\frac{ 9 \ 10^9 (1.6 \ 10^{-19})^2 }{1.4142}$ 9 109 1.6 10-19 1.6 10-19 / 1.4142

W = 1.63 10⁻²⁸ J

b) the two electrons are fixed, what is the work to bring another electron to x₃ = 3.00 m y₃ = 0

in this case we have two fixed electrons

U = k $( \frac{q_1q_3}{r_{13} } + \frac{q_2q_3}{r_{23} } )$

in this case all charges are electrons

q₁ = q₂ = q₃ = q

W = U = k q² $( \frac{1}{r_{13} } + \frac{1}{r_{23} } )$

the distances are

r₁₃ = $\sqrt{(3-0)^2 + 0}$ RA (3.00 -0) 2 + 0

r₁₃ = 3

r₂₃ = $\sqrt{ 3^2 + 2^2}$ Ra (3 0) 2 + (2 0) 2

r₂₃ = √13

r₂₃ = 3.606 m

let's look for the job

W = U

let's calculate

W = ${9 \ 10^3 ( 1.6 10^{-19})^2 }({\frac{1}{3} + \frac{1}{3.606} } )$

W = 1.407 10⁻²⁷ J

c) the three electrons are fixed, we bring the four electron to x₄ = 3.00m,

y₄ = 4.00 m

W = U = k $( \frac{q_1q_4}{r_{14 }} + \frac{q_2q_4}{r_{24} } + \frac{q_3q_4}{r_{34} } )$

all charges are equal q₁ = q₂ = q₃ = q₄ = q

W = k q² $(\frac{1}{r_{14} } + \frac{1}{r_{24} } + \frac{1}{r_{34} } )$

let's look for the distances

r₁₄ = $\sqrt{3^2 +4^2}$

r₁₄ = 5 m

r₂₄ = $\sqrt{3^2 + ( 4-2)^2}$

r₂₄ = √13 = 3.606 m

r₃₄ = $\sqrt{(3-3)^2 + (4-0)^2}$

r₃₄ = 4 m

we calculate

W = 9 10⁹ (1.6 10⁻¹⁹)² $( \frac{1}{5} + \frac{1}{3.606} + \frac{1}{4} )$

W = 1.68 10⁻²⁸ J

d) we take the proton to the location x5 = 1m y5 = 1m

W = U = k $( \frac{q_1q_5}{r_{15} } + \frac{q_2q_5}{r_{25} } + \frac{q_3q_5}{r_{35} } + \frac{q_4q_5}{r_{45} } )$

in this case the charges have the same values but charge 5 is positive and the others negative, so the products of the charges give a negative value

W = - k q² $( \frac{1}{r_{15} } + \frac{1}{r_{25} } + \frac{1}{r_{35} } + \frac{1}{r_{45} } )$

we look for distances

r₁₅ = $\sqrt{ 1^2 +1^2}$ Ra (1-0) 2 + (1-0) 2

r₁₅ = √ 2 = 1.4142 m

r₂₅ = $\sqrt{ (2-1)^2 +1^2}$

r₂₅ = √2 = 1.4142 m

r₃₅ = $\sqrt{ ( 3-1)^2 +1^2}$

r₃₅ = √5 = 2.236 m

r₄₅ = $\sqrt{ (3-1)^2 + (4-1)^2}$

r₄₅ = √13 = 3.606 m

we calculate

W = - 9 10⁹ (1.6 10⁻¹⁹)² $( \frac{1}{1.4142} +\frac{1}{1.4142} + \frac{1}{2.236} + \frac{1}{3.606} )$

W = - 4.93 10⁻²⁸ J

3 0

3 years ago

How much energy (in kj) do 3.0 moles of photons, all with a wavelength of 670 nm, contain? how much energy (in kj) do 3.0 moles

Kisachek [45]

1 mole of photons contain $6.023 \cdot 10^{23}$ photons (Avogadro number). This means that 3.0 moles of photons contain
$N=3\cdot 6.023 \cdot 10^{23} =1.81 \cdot 10^{24}$ photons.

The wavelength of the light in the problem is $\lambda=670 nm=670\cdot 10^{-9}m$ , so the frequency is
$f= \frac{c}{\lambda}= \frac{3\cdot 10^8 m/s}{670 \cdot 10^{-9}m}=4.48 \cdot 10^{14}Hz$

The energy carried by a single photon is
$E=hf$
where $h=6.62 \cdot 10^{-34}Js$ is the Planck constant, while f is the frequency. Since this is the energy carried by a single photon, the energy carried by 3.0 moles of photons will be the energy of the single photon multiplied by the total number of photons:
$E=Nhf=(1.81 \cdot 10^{24})(6.62 \cdot 10^{-34}Js)(4.48 \cdot 10^{14}Hz )=5.36 \cdot 10^5 J$
which corresponds to E=536 kJ.

4 0

3 years ago

Which statement is a correct expression of the Law of Conservation of Mass?

DiKsa [7]

<span>The correct answer is B. The law of conservation of mass states that the mass of an isolated system is neither created nor destroy by chemical reaction or physical transformation. This means that the mass of subtances in an isolated system remains constant, it can not decrease and it can not increase.</span>

7 0

4 years ago

Read 2 more answers

Which term is defined as the ratio of the speed of light in a vacuum to the speed of light in the material it is passing through

KATRIN_1 [288]

Answer:

Index of refraction

Explanation:

or refractive index

5 0

3 years ago

How many neutrons does element x have if it’s atomic number is 40 and it’s mass number is 82?

Black_prince [1.1K]

The atomic number gives you the number of protons element x has. Since the mass of protons and neutrons are almost similar(around 1 amu), the mass number can be thought of as the sum of protons and neutrons. so if element x whose atomic number is 40 has a mass number of 82, then we know that 42 of those must be neutrons.

4 0

3 years ago