When ultraviolet light with a wavelength of 254 nm falls on a clean copper surface, the stopping potential necessary to stop emission of photoelectrons is 0.181 v. part a what is the photoelectric threshold wavelength for this copper surface?
The photoelectric threshold wavelength for this copper surface is 264 nm
Further explanationThe term of package of electromagnetic wave radiation energy was first introduced by Max Planck. He termed it with photons with the magnitude is :
[tex]\large {\boxed {E = h \times f}}[/tex]
E = Energi of A Photon ( Joule )
h = Planck's Constant ( 6.63 × 10⁻³⁴ Js )
f = Frequency of Eletromagnetic Wave ( Hz )
The photoelectric effect is an effect in which electrons are released from the metal surface when illuminated by electromagnetic waves with large enough of radiation energy.
[tex]\large {\boxed {E = \frac{1}{2}mv^2 + \Phi}}[/tex]
[tex]\large {\boxed {E = qV + \Phi}}[/tex]
E = Energi of A Photon ( Joule )
m = Mass of an Electron ( kg )
v = Electron Release Speed ( m/s )
Ф = Work Function of Metal ( Joule )
q = Charge of an Electron ( Coulomb )
V = Stopping Potential ( Volt )
Let us now tackle the problem !
Given:
λ = 254 nm = 2,54 × 10⁻⁷ m
V = 0.181 Volt
c = 3 × 10⁸ m/s
h = 6.63 × 10⁻³⁴ Js
q = 1.6 × 10⁻¹⁹ C
Unknown:
λ₀ = ?
Solution:
[tex]E = qV + \Phi[/tex]
[tex]h f = qV + h f_o[/tex]
[tex]h \frac{c}{\lambda} = qV + h \frac{c}{\lambda_o}[/tex]
[tex]6.63 \times 10^{-34} \times \frac{3 \times 10^8}{2.54 \times 10^{-7}} = 1.6 \times 10^{-19}(0.181) + 6.63 \times 10^{-34} \times \frac{3 \times 10^8}{\lambda_o}[/tex]
[tex]7.83 \times 10^{-19} = 2.896 \times 10^{-20} + \frac{1.989 \times 10^{-25}}{\lambda_o}[/tex]
[tex]\frac{1.989 \times 10^{-25}}{\lambda_o} = 7.83 \times 10^{-19} - 2.896 \times 10^{-20}[/tex]
[tex]\lambda_o \approx 2.64 \times 10^{-7} ~ m[/tex]
[tex]\large {\boxed{\lambda_o \approx 264 ~ nm} }[/tex]
Learn morePhotoelectric Effect : https://brainly.com/question/1408276Statements about the Photoelectric Effect : https://brainly.com/question/9260704Rutherford model and Photoelecric Effect : https://brainly.com/question/1458544Answer detailsGrade: College
Subject: Physics
Chapter: Quantum Physics
Keywords: Quantum , Physics , Photoelectric , Effect , Threshold , Wavelength , Stopping , Potential , Copper , Surface , Ultraviolet , Light
The magnetic flux through each loop of a 75-loop coil is given by (8.8t−0.51t3)×10−2t⋅m2, where the time t is in seconds.
The magnetic flux through each loop of a coil can be calculated using the given expression. The magnetic moment of the coil can be found by multiplying the current and the area of the loop. Faraday's law states that a changing magnetic flux induces an electromotive force in a circuit.
Explanation:The magnetic flux through each loop of a 75-loop coil can be calculated using the expression: (8.8t−0.51t³)×10−²t⋅m², where t represents time in seconds. The magnetic flux is a measure of the magnetic field passing through a surface. It can also be calculated using the product of the magnetic field strength and the area of the loop.
The magnetic moment of the coil can be found using the formula μ = IA, where I is the current and A is the area of the loop. Substituting the given values, we find that the magnetic moment equals 2.5 × 10⁻⁶ A·m².
Faraday's law states that a changing magnetic flux through a loop induces an electromotive force (emf) in the circuit. Therefore, if the current through the coil varies with time, the magnetic flux will change accordingly and an emf will be induced in the circuit.
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Unknown element X is a metal that ionically bonds to sulfur.
Is the formula, X3S feasible? Why or why not?
A) It is feasible. The three metallic ions each receive an electron from sulfur.
B) No, it is not feasible. Sulfur cannot give three electrons to the metal since the sulfide ion has a -2 charge.
C) No, it is not feasible. The metallic ion X only has one valence electron and the sulfide ion receives two electrons.
D) No, it is not feasible. Three metallic ions cannot provide the exact number of electrons that one sulfur needs for the ionic bond.
The electrons in the beam of a television tube have a kinetic energy of 2.20 10-15 j. initially, the electrons move horizontally from west to east. the vertical component of the earth's magnetic field points down, toward the surface of the earth, and has a magnitude of 3.00 10-5 t. (a) in what direction are the electrons deflected by this field component? due north due south due east due west (b) what is the magnitude of the acceleration of an electron in part (a)? m/s2
A satellite is in a circular orbit about the earth at a distance of one earth radius above the surface. what is the velocity of the satellite? (the radius of the earth is 6400 km and the mass of the earth is 5.98 * 1024 kg)
Which listed property of alternating current is the MOST LIKELY reason it was chosen over direct current to provide electricity across the country? A) can power devices B) can be used in houses C) current changes direction D) can be transformed to different voltages
The index of refraction for red light in a certain liquid is 1.303; the index of refraction for violet light in the same liquid is 1.326. part a find the dispersion θv−θr for red and violet light when both are incident on the flat surface of the liquid at an angle of 45.00 ∘ to the normal.
A girl is running toward the front of a train at 10 m/s. If the train is going 75 m/s on the Southbound tracks, what is the speed of the train relative to the girl?
The speed of the train relative to the girl is 65 m/s.
Explanation:The speed of the train relative to the girl can be calculated by subtracting the girl's speed from the train's speed. In this case, the train is moving at 75 m/s and the girl is running towards the front of the train at 10 m/s. So the speed of the train relative to the girl would be 75 m/s - 10 m/s = 65 m/s.
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The correct option is B. 65 m/s, South.
The given problem can be solved using concepts of relative motion.
Given that the girl is running toward the front of a train at 10 m/s and the train is going 75 m/s on the Southbound tracks. Hence, both the girl and the train are moving in the same direction, i.e. southwards.
So, the speed of the train relative to the girl can be given as:
[tex]v_{tg} = v_t - v_g[/tex]
where, [tex]v_{tg}[/tex] is the speed of train with respect to the girl
[tex]v_t[/tex] is the speed of train
[tex]v_g[/tex] is the speed of the girl
[tex]\therefore v_{tg} = 75 \hspace{0.8mm} m/s - 10 \hspace{0.8mm} m/s[/tex]
or, [tex]v_{tg} = 65 \hspace{0.8mm} m/s[/tex]
Hence, the speed of the train relative to the girl is 65 m/s due south.
The complete question is:
A girl is running toward the front of a train at 10 m/s. If the train is going 75 m/s on the Southbound tracks, what is the speed of the train relative to the girl?
A. 10 m/s, South
B. 65 m/s, South
C. 65 m/s, North
D. 10 m/s, North
A uniform magnetic field points upward, parallel to the page, and has a magnitude of 7.85 mt. a negatively charged particle (q=−3.32 μc, m=2.05 pg) moves through this field with a speed of 67.3 km/s perpendicular to the magnetic field, as shown. the magnetic force on this particle is a centripetal force and causes the particle to move in a circular path. what is the radius of the particle's circular path?
The magnetic force on a charged particle moving through a magnetic field perpendicular to its velocity can cause the particle to move in a circular path. The radius of this path can be calculated using the formula r = mv/qB, resulting in an approximate radius of 42 millimeters for the given parameters.
Explanation:In physics, one of the forces that can cause a particle to undergo uniform circular motion is the magnetic force. This happens when a charged particle moves in a direction perpendicular to a magnetic field. The magnetic force, being perpendicular to the velocity of the particle, acts as a centripetal force, constantly changing the direction of the particle's velocity, thus causing the particle to move in a circular path. The radius of this circular path can be obtained using the equation for the magnetic force acting on a moving charged particle, F = qvB, where q is the charge of the particle, v is the speed of the particle, and B is the magnetic field strength.
So the magnetic force equals the centripetal force when qvB = mv²/r, which allows us to solve for r, the radius of the path: r = mv/qB.
Substituting the given values: r = (2.05*10^-12 kg * 67.3*10^3 m/s) / (3.32*10^-6 C * 7.85 T), we find the radius r is about 0.042 meters or 42 millimeters. Note we have included unit conversions for mass m from picograms (pg) to kilograms (kg), speed v from kilometers per second (km/s) to meters per second (m/s), and charge q from microcoulombs (μC) to coulombs (C).
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The radius of the particle's circular path is 42 millimeters.
Given:
A uniform magnetic field with magnitude B = 7.85 mT
A negatively charged particle with charge q = -3.32 μC = -3.32 × 10⁻⁶ C and mass m = 2.05 pg = 2.05 × 10⁻¹⁵ kg
The particle moves with a speed of v = 67.3 km/s = 67.3 × 10³ m/s perpendicular to the magnetic field
The magnetic force on a charged particle moving in a magnetic field is given by the equation:
F = qvB sinθ
where θ is the angle between the velocity of the particle and the magnetic field. In this case, θ = 90°, so sinθ = 1. Therefore, the magnetic force on the particle is:
F = qvB = (-3.32 × 10⁻⁶ C)(67.3 × 10³ m/s)(7.85 × 10⁻³ T) = 1.75 × 10⁻² N
The magnetic force is also the centripetal force that keeps the particle moving in a circular path. Therefore, we can equate the magnetic force to the centripetal force to find the radius of the particle's circular path:
F = mv²/r
Solving for r, we get:
r = mv²/F = (2.05 × 10⁻¹⁵ kg)(67.3 × 10³ m/s)²/(1.75 × 10⁻² N) = 0.042 m = 42 mm
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What are (a) the kinetic energy, (b) the rest energy, and (c) the total energy of a 1.50 g particle with a speed of 0.600 c ?
When the angle of elevation of the sun is 64°, a pole that is tilted at an angle of 19° directly away from the sun casts a shadow 21 feet long on level ground. approximate the length of the pole to the nearest foot?
Answer:
Length of the pole is 27ft. ( rouding up to the nearest foot)
Explanation:
To solve this problem you need to understand that the the shadow cast by the pole on the ground connected to the pole itself and to the imaginary line of sun light forms a triangle with 3 different angles, please see the drawing to a better understanding.
* The sum of the internal angles of any triangle must be 180° then;
α: angle of the elevation of the sun= 64°
angle of the pole to the ground= (90-19)= 71°
β = 180 - ( 64+71) = 45°
*To find the length of the pole we can use the law of Sines;
|BC| / sin (α) = |AC| / sin (β)
|BC|= Length of the pole
|AC|= shadow of the pole on the ground which is known to be 21 ft
|BC| / sin (64°) = 21 / sin (45°)
|BC|= 21 x [sin (64°)/ sin (45°)]
|BC|= 21 x 1.27≅ 26.67 ft
"the temperature of a student's skin is 33.0°c. at what wavelength does the radiation emitted from the skin reach its peak?"
The peak wavelength of radiation emitted from human skin at 33.0°C is approximately 9465.7 nm or about 9.465 microns, calculated using Wien's displacement law.
Explanation:The student's question about the peak wavelength of radiation emitted from the skin at a certain temperature relates to Wien's displacement law. This law states that the peak wavelength of the radiation is inversely proportional to the temperature of the radiating body when the temperature is in Kelvin. Firstly, we need to convert the skin temperature from Celsius to Kelvin, which would be 33.0°C + 273.15 = 306.15 K. Using Wien's law (with a constant of approximately 2.898 x 10^6 nm·K), we can calculate the peak wavelength with the formula λ(max) = b / T. So, the peak wavelength would be λ(max) = 2.898 x 10^6 nm·K / 306.15 K, which gives us a peak wavelength of approximately 9465.7 nm or about 9.465 microns.
What equation would you use to calculate the ideal mechanical advantage of a wheel and axle if the input force is applied to the axle?
Most objects emit infrared energy. how do humans recognize this? A.their skin senses it as warmth B. Their vision becomes clearer C. They experience goose bumps on their skin D. They see light emitted from the object
Answer: The correct answer is "their skin senses it as warmth".
Explanation:
Electromagnetic wave: the direction of electric field and magnetic field are perpendicular to the direction to the propagation of the wave. It travels with the speed of the light.
For example, X-rays, gamma rays, infrared rays and visible region.
Infrared radiation: The range of the wavelength is from 700 nm to 1 mm. It is longer than the visible light. It is a part of the electromagnetic spectrum.
The infrared radiations cannot be seen by naked eyes of human. It can be felt by the human being. They can sense it as heat.
It is given in the problem that most objects emit infrared energy. Human can feel this infrared radiation. Their skin senses it as warmth.
Solar radiation falls on earth's surface at a rate of 1900 w/m2 . assuming that the radiation has an average wavelength of 560 nm, how many photons per square meter per second fall on the surfaces? the speed of light is 3 × 108 m/s and planck's constant is 6.62607 × 10−34 j · s. answer in units of photon/m2 · s.
The number of photons per square meter per second falling on the earth's surface, given the solar radiation rate and average wavelength is calculated to be 5.36 x 10²¹ photons/m2·s.
Explanation:The energy of the average visible photon is calculated using the formula E= hc/λ, where h is Planck's constant, c is the speed of light and λ is the wavelength. With the given values, we get the energy E by substituting h=6.62607 × 10⁻³⁴ J·s, c=3 × 108 m/s, and λ=560 × 10⁻⁹ m resulting in E= 3.546 × 10⁻¹⁹ J. The number of photons per meter square per second can be calculated by dividing the rate of solar radiation, 1900 W/m2 or 1900 J/s·m2 by the energy per photon, yielding 5.36 x 10²¹ photons/m2·s.
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Which change occurs when an atom undergoes decay?
Nikolas had an idea that he could use the compressed carbon dioxide in a fire extinguisher to propel him on his skateboard.
Which of Newton’s laws would he have used to come up with this idea?
Answer:
Newton's Third Law
Explanation:
Did the assignment
You illuminate a slit of width 0.0675 mm with light of wavelength 711 nm and observe the resulting diffraction pattern on a screen that is situated 2.21 m from the slit. what is the width, in centimeters, of the pattern\'s central maximum?
What factors determine power
A particle traveling in a straight line is located at the point (1, 0, −1) and has speed 3 at time t = 0. the particle moves toward the point (3, 4, 3) with constant acceleration 2i+ 4j+ 4k. find the velocity v(t) and the position r(t) of the particle at time t.
We first observe that the particle moves in the direction of the vector
[tex](3\,\vec\imath + 4\,\vec\jmath + 3\,\vec k) - (\vec\imath - \vec k) = 2\,\vec\imath + 4\,\vec\jmath + 4\,\vec k[/tex]
so the initial velocity vector [tex]\vec v_0[/tex] is parallel to this vector. Given its initial speed is 3 at [tex]t=0[/tex], this means for some scalar constant [tex]c>0[/tex], we have
[tex]\vec v_0 = 2c\,\vec\imath + 4c\,\vec\jmath + 4c\,\vec k[/tex]
such that
[tex]\|\vec v_0\| = \sqrt{(2c)^2 + (4c)^2 + (4c)^2} = 6c = 3 \implies c = \dfrac12[/tex]
so that the initial velocity is
[tex]\vec v_0 = \vec\imath + 2\,\vec\jmath + 2\,\vec k[/tex]
Now, use the fundamental theorem of calculus to compute the velocity and position functions.
[tex]\displaystyle \vec v(t) = \vec v_0 + \int_0^t \vec a(u) \, du \\\\ ~~~~ = (\vec\imath + 2\,\vec\jmath + 2\,\vec k) + \int_0^t (2\,\vec\imath + 4\,\vec\jmath+4\,\vec k) \, du \\\\ ~~~~ = (\vec\imath + 2\,\vec\jmath + 2\,\vec k) + (2t\,\vec\imath + 4t\,\vec\jmath+4t\,\vec k) \\\\ ~~~~ = (1 +2t)\,\vec\imath + (2+4t)\,\vec\jmath + (2+4t)\,\vec k[/tex]
[tex]\displaystyle \vec r(t) = \vec r_0 + \int_0^t \vec v(u) \, du \\\\ ~~~~ = (\vec\imath - \vec k) + \int_0^t \left((1 +2u)\,\vec\imath + (2+4u)\,\vec\jmath + (2+4u)\,\vec k\right) \, du \\\\ ~~~~ = (\vec\imath - \vec k) + ((t+t^2)\,\vec\imath + (2t+2t^2)\,\vec\jmath + (2t+2t^2)\,\vec k) \\\\ ~~~~ = (t^2+t+1)\,\vec\imath + (2t^2+2t)\,\vec\jmath + (2t^2+2t-1)\,\vec k[/tex]
A child wants to pump up a bicycle tire so that its pressure is 1.2 × 105 pa above that of atmospheric pressure. if the child uses a pump with a circular piston 0.035 m in diameter, what force must the child exert?
Answer:
The force exerted by the child is 460.8 N
Explanation:
We have given that pressure [tex]P=1.2\times 10^5pa[/tex]
Radius of the circular piston r = 0.035 m
So area [tex]A=\pi r^2=3.14\times 0.035^2=0.003846m^2[/tex]
We have to find the force exerted by the child
We know that force is given by
[tex]Force=pressure\times area[/tex]
So force will be [tex]Force=1.2\times 10^5\times 0.00384=460.8N[/tex]
So the force exerted by the child is 460.8 N
Pressure
The definition of pressure is given as the force per unit area
The unit of pressure is Newton
Explanation:
Given data
Pressure = 1.2 × 105 pa
diameter = 0.035 m
We know that the expression for pressure is given as
Pressure = Force/Area
Making Force the subject of the formula
Force = Pressure * Area
But we do not know the area
Now let us find the area
Area = πd^2/4
Area= (3.142*(0.035)^2)/4
Area = 3.142*0.001225/4
Area= 0.00384895/4
Area= 0.000962 m^2
Force = 1.2 × 10^5*0.000962
Force = 115.44 Newton
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What is the energy of a photon whose frequency is 6.0 x 1020 hz?
The energy of a photon with a frequency of 6.0 x 1020 Hz is 3.976 x 10-13 joules.
To find the energy of a photon, we can use the equation E = hf, where
E represents the energy, h is Planck's constant (6.626 x 10-34 J·s), and f is the frequency of the photon. Substituting the given frequency (f = 6.0 x 1020 Hz) into the equation and using Planck's constant, we calculate the energy (E) as follows:
E = (6.626 x 10-34 J·s) (6.0 x 1020 Hz) = 3.976 x 10-13 J. Although this amount of energy might seem very small, it's important to remember that visible light and other forms of electromagnetic radiation consist of vast numbers of photons, which collectively can have a significant amount of energy.
Marisol and mimi walked the same distance from their school to a shopping mall. marisol walked 2 miles per hour, while mimi left 1 hour later and walked 3 miles per hour. if they reached the mall at the same time, how far from the mall is their school? answers
Sonic boom from a plane is an example of a shockwave. Give another example where a shockwave is produced
The distance between two consecutive crests is 2.5 meters. Which characteristic of the wave does this distance represent?
amplitude
frequency
period
wavelength
phase
The main organ of the respiratory system
Compute the resistance in ohms of a silver block 10 cm long and 0.10 cm2 in cross-sectional area. ( = 1.63 x 10-6 ohm-cm)
Answer:
1.6 x 10^-4 Ω
Explanation:
what happens when ice transform into steam
Answer:
The thermal kinetic energy of the molecules is raised
Explanation:
As it takes some amount of heat energy to be converted to thermal energy to turn ice into water and water into a stream. As this state change, the temperature will rise again. As the energy generated is being measured in Joule, a more commonly studied unit is a calorie. As matter vary in their capacity to absorb heat. Like ice needs about 0.50 as specific heat, water as 1.00 and stream 0.48 cal/g in degrees C. As the matter is heated the latent or hidden energy is released and tends to remain until the material changes its state.change 75 inches to feet
(a) an electron has kinetic energy 5.00 ev. find its wavelength.
The wavelength of an electron with a given kinetic energy of 5.00 eV can be found using the de Broglie wavelength formula and first converting the kinetic energy into joules.
Explanation:To find the wavelength of the electron with kinetic energy of 5.00 eV, we will use the de Broglie wavelength formula, which links a particle's momentum to its wavelength. This is given by λ = h/p where λ is the wavelength, h is Planck's constant (6.626 x 10-34 Js), and p is the momentum of the particle.
First, we need to convert the kinetic energy into joules. The energy in joules (E) is given by E = K x q, where K is the kinetic energy in electronvolts (eV) and q is the electron charge (1.602 x 10-19 C). For the given energy of 5.00 eV, the energy in joules will be E = 5.00 eV x 1.602 x 10-19 C/eV = 8.01 x 10-19 J.
Now, we can calculate the electron's momentum using the relation p = √(2mE), where m is the electron's mass (9.109 x 10-31 kg). After solving, the momentum is used in de Broglie's formula to find the wavelength.