Answer:
#_foton2 = 2.96 10¹⁶ photon / s
Explanation:
We are going to solve this exercise in parts, first we will calculate how many photons are in the beam and then the amount that pass through the pinhole.
To find the energy of a photon, let's use the Planck relationship
E = h f
c = λ f
we substitute
E₀ = h c /λ
E₀ = 6.63 10⁻³⁴ 3 10⁸/337 10⁻⁹
E₀ = 5.90 10⁻¹⁹ J
Now we can use a direct ratio rule to find out the number of photons in the beam. If 1 photon has an energy E₀, how many photons are in an energy 5.00W
# _foton = 1 5/ E₀ = 1 5 / 5.90 10⁻¹⁹
#_foton = 8.5 10¹⁸ photons / s
This number of photons is uniformly distributed in the area of the circle with diameter 5.90mm = 5.90 10⁻³m
R= d/2= 2.95 10⁻³ m
r = d/2 = 0.55 10⁻³ m
let's find the beam area
A = π R²
A = π (2.95 10⁻³)²
A = 2.73 10⁻⁵ m²
the pinhole area
a = π r²
a = π (0.55 10⁻³)²
a = 9.50 10⁻⁷ m²
Let's use another direct ratio (rule of three) if there are 8.5 1018 photons / s in an area A how many photons pass through the area at
# _foton2 = 8.5 10¹⁸ a / A
# _fotn2 = 8.5 10¹⁸ 9.50 10⁻⁷ /2.73 10⁻⁵
#_foton2 = 2.96 10¹⁶ photon / s
What are the two main regions of the body?
cranial and spinal
axial and appendicular
trunk and limbs
muscular and skeletal
Answer: Your correct answer would be the second option; axial and appendicular. The axial region makes up the axis of the human body, this includes your head, neck, etc. The appendicular region makes up the parts of the human body that connects to the axial region, for example limbs and appendages.
What do the skull and vertebrae have in common
Answer: ok
Explanation: ok
what are fundamental quantities
Answer: length, luminous intensity,mass, time, temperature, electric current, amount of a substance.
Explanation:
A 65-turn coil has a diameter of 14 cm. Find the magnitude of the emf induced in the coil (in V) if it is placed in a spatially uniform magnetic field of magnitude 0.65 T so that the face of the coil makes the following angles with the magnetic field, and the magnetic field is reduced to zero uniformly in 0.2 s.
Answer:
The value is [tex]\epsilon = 3.24 \ V[/tex]
Explanation:
From the question we are told that
The number of turns is n = 65
The diameter is [tex]d = 14 \ cm = 0.14 \ m[/tex]
The magnetic field is [tex]B_1 = 0.65 \ T[/tex]
The time taken for the magnetic field to be reduced to [tex]B_2 = 0 \ T[/tex] is [tex]\Delta t = 0.2 s[/tex]
Generally the magnitude of the induced emf is mathematically represented as
[tex]\epsilon = N * \frac{B_1 - B_2}{\Delta t } * A[/tex]
Here A is the area of the coil which is mathematically represented as
[tex]A = \pi * \frac{d^2}{4}[/tex]
=> [tex]A = 3.142 * \frac{0.14^2}{4}[/tex]
=> [tex]A = 0.0154 \ m^2[/tex]
So
[tex]\epsilon = 65 * \frac{0.65 - 0 }{0.2 } * 0.01534[/tex]
=> [tex]\epsilon = 3.24 \ V[/tex]
A 1000 kg car and a 2000 kg car are lifted the same distance in a
mechanic's shop. Neglecting friction, raising the more massive car
requires
Answer:
Twice as much work
Explanation:
A ferry crossed the Potomac River four times in one day. The ferry traveled the same distance for each trip, but it took different amounts of time. The time for each trip is shown in the table below. Time for Ferry to Cross on Different Trips Trip Number Time Trip 1 10 minutes Trip 2 11 minutes Trip 3 9 minutes Trip 4 12 minutes On which trip did the ferry travel the fastest? A. Trip 3 B. Trip 2 C. Trip 4 D. Trip 1
Explanation:
trip 3 ( 9 minutes)
If the ferry is moving at a faster speed, it will travel the same distance in a shorter time. The ferry crossed the river the fastest on Trip 3 because it took the shortest amount of time on that trip.
A force of 400-N pushes on a 25-kg box horizontally. The box accelerates at 9 m/s? Find the coefficient of kinetic friction between the box and floor.
Answer:
0.69Explanation:
Using the Newtons law of motion;
[tex]\sum Fx = ma_x\\Fm - Ff = ma_x[/tex]
Fm is the moving force = 400N
Ff is the frictional force = μR
μ is the coefficient of kinetic friction
R is the reaction = mg
m is the mass
a is the acceleration
The equation becomes;
[tex]Fm - \mu R = ma_x\\Fm - \mu mg = ma_x\\400- \mu (25)(9.8) = 25(9)\\400 - 254.8 \mu = 225\\- 254.8 \mu = 225 - 400\\- 254.8 \mu = -175\\ \mu = \frac{-175}{- 254.8} \\\mu = 0.69[/tex]
Hence the coefficient of kinetic friction between the box and floor is 0.69
The coefficient of kinetic friction between the box and the floor is 0.714.
Friction: This can be defined as the force that tends to oppose two surfaces in motion.
The question above can be solved using the formula
F-ma = mgμ................. Equation 1
Where F = Force applied to push the box, m = mass of the box, a = acceleration of the box, μ = coefficient of kinetic friction, g = acceleration due to gravity.
make μ the subject of the equation
μ = (F-ma)/mg................ Equation 2
From the question,
Given: F = 400 N, m = 25 kg, a = 9 m/s²,
Constant: g = 9.8 m/s²
Substitute these values into equation 2
μ = [400-(25×9)]/(25×9.8)
μ = (400-225)/245
μ = 175/245
μ = 0.714
Hence, the coefficient of kinetic friction between the box and the floor is 0.714.
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A carriage of 20 kg is pulled with a force of 35 N. How far the carriage will go
doing 95 J work?
Answer:
2.71 m
Explanation:
Force is the product of mass and acceleration
F=m*a
Work done is the product of force and distance
Work done=F*d
In this case;
F= 35 N
Work done = 95 J
95 =35 * d
95 /35 = d
2.71 m= d
If one person is applying an upward force equal to 60 N at one end, at what location on the board is the other person applying an upward force
Answer:
When one person applies force f1 = 60 N at one end, the other person applies f2 = 160 - 60 = 100 N. The torques about the center must balance. Thus the distances from the center d1 and d2 must be such that f1*d1 = f2*d2, or 60*1.5 = 100*d2, so d2=0.9. Thus f2 must be applied at a point 1.5 + 0.9 = 2.4 m from the end where f1 is applied.
A 10-turn ideal solenoid has an inductance of 3.5 mH. When the solenoid carries a current of 2.0 A the magnetic flux through each turn is:
Answer:
7 * 10^-4Wb
Explanation:
The magnetic flux is the product of the inductance and current
Magnetic flux = LI
L is the inductance = 3.5mH
I is the current = 2.0A
Number of turns N = 2A
Since for a 10-turn solenoid, L = 3.5mH
For a one-turn solenoid, L = 3.5/10 = 0.35mH
magnetic flux = 0.35mH * 2
magnetic flux = 0.35 * 10^-3 * 2
magnetic flux = 0.7* 10^-3
Magnetic flux = 7 * 10^-4Wb
Hence the magnetic flux through each turn is 7 * 10^-4Wb
The magnetic flux through each turn is 7 ×10⁻⁴ Wb. The magnetic flux is the product of the inductance and current.
What is megnetic flux?
The surface integral of the normal component of the magnetic field B across a surface is the magnetic flux through that surface. It is commonly indicated by the letters B.
The weber is the SI unit for magnetic flux, while the maxwell is the CGS unit.
The given data in the problem is;
[tex]\rm \phi[/tex] is the magnetic flux =?
L is the inductance = 3.5mH
I is the current = 2.0A
N number of turns of solenoid = 2A
The inductance for the one turn is found by;
For a 10-turn solenoid, L = 3.5mH
For a one-turn solenoid, L = 3.5/10 = 0.35mH
The megnetic flux through each turn is found by;
[tex]\rm \phi = L \times I \\\\ \rm \phi = 0.35 \times 10^{-3}\times 2\\\\ \rm \phi =7 \times 10^{-4}[/tex]
Hence the magnetic flux through each turn is 7 ×10⁻⁴ Wb.
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A motobike's tire rotates with a constant angular speed of 62.8 rad/s. The radius of a tire is 30cm. Assuming that no slipping occurs, the number of
revolutions of the tire in one second is:
a.
12.6
b.
20
C.
18.8
d.
10
Answer:
10
Explanation:
Given that :
Angular speed (w) = 62.8 rad/s
Radius of tire (r) = 30 cm
Number of revolutions per second :
s = 2πr
s = 2π * 0.3 = 1.8849555
The number or revolutions per second :
θ = s / r
θ = 1.884955 / 0.3
θ = 6.283185 rad
Number of revolutions per second :
62.8 / 6.283185
= 9.9949309
= 10
In an RC parallel circuit, Et = 480 V, R = 50ko, and XC = 47 ko. What is the reactive power?
Correct question is;
In an RC parallel circuit, Et = 480 V, R = 50kΩ, and XC = 47 kΩ. What is the reactive power?
Answer:
P_r = 4.9 VARs
Explanation:
We are given;
Total voltage: Et = 480 V
Resistance; R = 50kΩ = 50000 Ω
Capacitive reactance; XC = 47 kΩ = 47000 Ω
Formula for current across the capacitor is;
Et = I_c • XC
I_c = Et/XC
l_c = 480/47000
I_c = 0.01021 A
Formula for reactive power is;
P_r = (I_c)² × XC
P_r = 0.01021² × 47000
P_r = 4.9 VARs
matter can be a solid, lquid or gas. but you cannot see the particles or adoms that make up matter because they are
Answer:
very small...
Explanation:
i guess... but i may be missing something. the question feels too straightforward
Gravity pushes against all objects, trying to crush it. What pushes against gravity in: a main sequence star, a white dwarf, a neutron star, and a black hole?
Answer:
heat pressure, neutron degeneracy, electron degeneracy,nothing.
Explanation:
In main sequence star, gravity's inward pull is greatly balanced by the heat pressure. In the white dwarf, gravity is mainly balanced by the electron degeneracy pressure that arises from the fact that the electrons are fermions and they obey the Pauli's exclusion principle. So there is no two electrons that have the same the four quantum numbers.
While in neutron star, the neutron degeneracy pressure obeys the Pauli's exclusion principle that gives rise to the degeneracy pressure and noting pushes against the gravity in the black hole. Therefore the correct option is the heat pressure, neutron degeneracy, electron degeneracy and nothing.
A student drops a 2.4-kg ball. It’s speed right before hitting the ground is 5 m/s. If 15 J of energy was transferred to the environment as the ball fell, what was the total initial energy of the ball?
21 J
30 J
45 J
6 J
The answer is 45J
Don’t know how to explain sorry
Only 35 % of the intensity of a polarized light wave passes through a polarizing filter. What is the angle between the electric field and the axis of the filter
Answer:
The angle between the electric field and the axis of the filter is 54⁰
Explanation:
Apply the equation for intensity of light through a polarizer.
[tex]I = I_oCos^2 \theta[/tex]
where;
I is the intensity of the transmitted light
I₀ is the intensity of the incident light
θ is the incident angle
If only 35 % of the intensity of a polarized light wave passes through a polarizing filter, then the ratio of the intensity of the transmitted light to that of the intensity of the incident light is given by;
[tex]\frac{I}{I_o} = Cos^2 \theta\\\\\frac{35}{100} = Cos^2 \theta\\\\Cos^2 \theta = 0.35\\\\Cos\theta = \sqrt{0.35} \\\\Cos\theta = 0.5916\\\\\theta = Cos^{-1}(0.5916)\\\\\theta = 54 ^0[/tex]
Therefore, the angle between the electric field and the axis of the filter is 54⁰
The angle between the electric field and the axis of the filter for the polarized light wave which passes through a polarizing filter is 54°.
What is electric field?The electric field is the field, which is surrounded by the electric charged. The electric field is the electric force per unit charge.
From the Malus's law, the intensity of the polarized beam can be calculated with the following formula.
[tex]I=I_o\cos^2\theta[/tex]
Here, (I₀) is the intensity of the polarized beam incident on the observer θ is the angle of incident.
It is given that only 35 % of the intensity of a polarized light wave passes through a polarizing filter.
The angle between the electric field and the axis of the filter can be found out using the above formula as,
[tex]35\%=(100\%)\cos^2\theta\\\theta=\cos^{-1}\sqrt{\left(\dfrac{35}{100}\right)}\\\theta=54^o[/tex]
Hence, the angle between the electric field and the axis of the filter for the polarized light wave which passes through a polarizing filter is 54°.
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A black widow spider hangs motionless from a web that extends vertically from the ceiling above. If the spider has a mass of 1.27 g, what is the tension in the web
Answer:
Tension = 0.012 N
Explanation:
If the black widow spider is hanging vertically motionless from the ceiling above. Then, the weight of the spider must be balancing the tension in the spider web. Therefore,
Tension = Weight
Tension = mg
where,
m = mass of spider = 1.27 g = 0.00127 kg
g = acceleration due to gravity = 9.8 m/s²
Therefore,
Tension = (0.00127 kg)(9.8 m/s²)
Tension = 0.012 N
How does the air pressure inside a tennis ball change when you hit it?
Two men, Joel and Jerry, push against a wall. Jerry stops after 10 min, while Joel is able 1) to push for 5.0 min longer. Compare the work they do. A) Both men do positive work, but Joel does 25% more work than Jerry. B) Both men do positive work, but Joel does 75% more work than Jerry. C) Both men do positive work, but Jerry does 50% more work than Joel. D) Both men do positive work, but Joel does 50% more work than Jerry E) Neither of them does any work.
Answer:
the correct answer is E
Explanation:
Work is defined by the expression
W = F. d
Where the bold indicates vectors, we can make the dot product explicit
W = F d cos θ
We can see that this definition of work the two men apply a force, but the wall does not move, so if there is no displacement the work is zero.
When checking the correct answer is E
does water not have anomalous expansion?
Explanation:
The anomalous expansion of water is an abnormal property of water whereby it expands instead of contracting when the temperature goes from 4o C to 0o C, and it becomes less dense. ... The density becomes less and less as it freezes because molecules of water normally form open crystal structures when in solid form.
please help im failing!!!
An object has density rho.
a. Suppose each of the object's three dimensions is increased by a factor of 2 without changing the material of which the object is made. Will the density change? If so, by what factor? Explain.
b. Suppose each of the object's three dimensions is increased by a factor of 2 without changing the object's mass. Will the density change? If so, by what factor? Explain.
Answer:
a. the density will not change
b. D' = 0.125 D
So, the density will change by a factor of 0.125
Explanation:
a.
Density is the material property and the value of density is constant for all solid materials. So, when the dimensions of the a solid are increased, while the material is same, then the material must be added to the object for increasing its dimensions. So, with the increase in the volume, the mass of the object also increases. And as a result the density of the object remains constant.
Since, here the material remains the same.
Therefore, the density will not change
b.
Density = mass/Volume
D = m/V ------------ equation (1)
Now,
V = LWH ----------- equation (2)
Now, if each dimension increases by a factor of 2, the volume becomes:
V' = (2L)(2W)(2H)
V' = 8 LWH
using equation (2)
V' = 8 V
So, for constant mass, density becomes:
D' = m/V'
D' = m/8V
using equation (1)
D' = D/8
D' = 0.125 D
So, the density will change by a factor of 0.125
(a) The density of the object will be reduced by one-eighth times on increasing the dimension by a factor of two and keeping the material constant.
(b) With constant mass and increasing the dimensions by a factor of 2, the density will reduce by the factor of 1/8.
What is density of object?The degree measure of the compactness of an object is known as the density of an object. Mathematically, it is expressed as the ratio of the mass of the object to its volume.
(a)
Let us consider an object of dimension 'a'. As per the above definition, the density of an object is,
[tex]\rho = \dfrac{m}{V}[/tex]
Here,
m is the mass of the object.
V is the volume of the object. And its value is, [tex]V = a^{3}[/tex].
So the density becomes,
[tex]\rho = \dfrac{m}{a^{3}}[/tex] ..............................................................(1)
Now, if the dimensions of the object is increased by a factor of 2. Then, new density becomes,
[tex]\rho' =\dfrac{m}{(2a) \times (2a) \times (2a)}\\\\\\ \rho' =\dfrac{m}{8a^{3}}\\\\[/tex]
Substitute the value of equation (1) in the above expression as,
[tex]\rho' =\dfrac{1}{8} \times \dfrac{m}{a^{3}}\\\\\rho' =\dfrac{1}{8} \times \rho[/tex]
Thus, we can conclude that the density of the object will be reduced by one-eighth times on increasing the dimension by a factor of two and keeping the material constant.
(b)
The density of the material is equal to the ratio of the mass of the object (m) and the volume of the object (V). So, if the mass remains unchanged and the dimensions increased by the factor of 2, then the result will remain same as the above part.
Thus, we can conclude that with constant mass and increasing the dimensions by a factor of 2, the density will reduce by the factor of 1/8.
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What's the temperature 414K in degrees Celsius?
Answer:
212 I think
Explanation:
I looked it up
Have you ever written a bio-data or an application letter? Share your experience in the
space below. (e.g. How did you find the experience? What was hard? What was easy?)
Leave the space blank if you have never written any of these.
Answer:
I found the experience tasking
Explanation:
I wouldn't say it was hard, neither was it easy. I'd rather go for something like it being tasking. It's worthy of note that it was my first time, and I think it's very normal especially when one hasn't been doing something of that nature previously. Of course I did my draft, which unsurprisingly happened to be not good enough, and I had to look for templates to guide me through the acceptable way.
I still did it in my own way, but in the right way. Ever since then though, I have never stuttered when writing application letters, as it had since then seem inborn
The experience of writing a bio-data or an application letter was quite a tasking goal, where proper structure is required.
The given problem is based on the fundamentals of bio-data. Biodata is a document that is used to display the biographical data about the work experience in any organization.
As per my experience it was neither hard nor easy. I'd rather go for something like it being tasking. It's worthy of note that it was my first time, and I think it's very normal especially when one hasn't been doing something of that nature previously. I did my draft, which unsurprisingly happened to be not good enough, and I had to look for templates to guide me through the acceptable way. I still did it in my own way, but in the right way. Ever since then though, I have never stuttered when writing application letters, as it had since then seem inborn.Thus, it is concluded that writing a bio-data or an application letter was quite a tasking goal, where proper structure is required.
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A football player kicks a football off a tee with a speed of 21 m/s at an angle of 51°.
a. What is the horizontal component of the velocity?
b. What is the vertical component of the velocity?
c. How long does it take the ball to reach its highest point?
d. What is the maximum height of the ball?
e. What is the total amount of time that the ball is in the air?
f. How far is the ball from the football player when it lands?
I would appreciate any help :)
Answer:
see explanation
Explanation:
Answer:
a. 13.22 m/s
b. 16.32
c. 1.664 s
d. 13.58
e. 3.328
f. 40.0m
Explanation:
This is basically what the guy said, i dunno if you saw the letters, but he added some at the end of every answer.
A boy throws a tell ball straight up . disregarding any effects of air resistance, the forces acting 9n the ball untill it returns to the ground is are
A light bulb uses 1.2 A when connected across a 120 V source. What is the resistance by the bulb?
A bird perched in a tree is balanced or unbalanced
Answer: Balanced
Explanation: When a bird is perched on a tree it is sitting still will stay still if the forces acting on it are balanced.
Suppose that a brass rod 2.0 m long expands 0.2 cm when its temperature is increased a certain amount. By how much will a brass rod 80 m long expand with the same change in temperature?
Answer:
0.08 m
Explanation:
Linear expansivity brass = 2 * 10^-5 C
Linear expansivity = change in length / (initial length * θ)
Change in length = 0.2cm = 0.002m
Initial length = 2m
2 * 10^-5 = 0.002 / (2 * θ)
(2 * 10^-5 * 2θ) = 0.002
4 * 10^-5θ = 0.002
θ = 0.002 / 4 * 10^-5
θ = 2 * 10^-3 / 4 * 10^-5
θ = 0.5 * 10^2
θ = 50°C
For a rod of original length 80m at the same temperature of 50°C
Linear expansivity = change in length / (initial length * θ)
Change in length = dL
2 * 10^-5 = dL / (80 * 50)
2 * 10^-5 * 80 * 50 = dL
160 * 10^-5 * 50 = dL
8000 * 10^-5 = dL
0.08 m = dL
Hence, change in length = 0.08m
what are the characteristics of image when object is between f1 and 2f1 for concave lense?
Answer:
The required diagram is shown in the figure. When an object is placed in front of the convex lens, i.e., between 2F
1
and F
1
, its image is formed beyond 2F
2
on the other side of the lens. The image is real, inverted and enlarged.
solution