The answer is B. the universe was created from a cosmic explosion.
It is called the Big Bang Theory, but actually there was no REAL explosion. What happened was the universe expanded from a really dense and hot superforce. There were no stars, atoms, and the like. This point was called "singularity,"- a mass that contained all the mass, and the space-time of the universe.
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
Two waves have the same speed. the first has twice the frequency of the second. compare the wavelength of the two waves. 1. the second has one third the wavelength of the first. 2. the first has half the wavelength of the second. 3. the first has one third the wavelength of the second. 4. the second has half the wavelength of the first. 5. they have the s
What factors determine power
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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A rod made from insulating material carries a net charge, while a copper sphere is neutral. The rod and the sphere do not touch. Is it possible for the rod and the sphere to (a) attract one another and (b) repel one another? Explain.
Answer:
Sphere R must be negative and Sphere S must be positive or neutral.
Explanation:
Castle Learning. Also the Rod diagram shows electrons in it and we know like charges repel and opposites attract, so the rod must repel Sphere R because it is negative and attract to Sphere S because it is the opposite.
A transformer is a device that increases or decreases voltage. t/f
Answer:
True.
Explanation:
A transformer is used either to increase or decrease the voltage.
It has two separate sets of coils of wire. The coils connected to the input voltage are called primary and the output coils are called secondary.
If number of windings (or coils) of wire in primary are less than the windings in secondary, it is a step up transformer because output voltage will be more than the input voltage. In this case the output voltage given out by the secondary will be more than the primary.
If the primary coils are more than the secondary, it is called a step down transformer. In this case, secondary voltage (output voltage) will be less than the primary.
An oscillating block - spring system has a mechanical energy of 1.10 j, and amplitude of 11.0 cm, and a maximum speed of 1.7 m/s. find the spring constant.
Which statement is true?
Voltage varies throughout a parallel circuit.
Voltage remains the same throughout a parallel circuit.
In a parallel circuit, the voltage remains constant throughout. An analogy using a bike path explanation further simplifies this concept.
Explanation:In the world of physics, it is true to say: 'Voltage remains the same throughout a parallel circuit'. To further illustrate this concept, consider a bike path as an analogy for a circuit.
If a parallel circuit was a bike path, then each 'fork' in the path represents a separate path for the electricity. Think of the voltage as a measure of energy.
Even though cyclists (or charges) can take different paths (resistors), they all start at the same height (self-same voltage).
Therefore, they all have the same amount of potential energy (voltage) at any point.
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The map of the world is overlaid with the boundaries of the tectonic plates. Look at the location marked with an asterisk (*). What geologic feature would expect to find at that location and why? A) rift zone; two plates move in opposite directions B) island arc; two oceanic plates meet at a convergent boundary C) mountains; two continental plates meet at a convergent boundary D) deep sea trench; subduction where two plates meet and one goes underneath the other
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.What is the energy q released in the first step of the thorium-232 decay chain? the atomic mass of 232 90th is 232.038054 u and the atomic mass of 228 88ra is 228.0301069 u. express your answer numerically in megaelectron volts?
Answer: The energy released in the given nuclear reaction is 4.98 MeV.
Explanation:
The equation for the alpha decay of Th-232 nucleus follows:
[tex]_{90}^{232}\textrm{Th}\rightarrow _{88}^{228}\textrm{Ra}+_{2}^{4}\textrm{He}[/tex]
We are given:
Mass of [tex]_{90}^{232}\textrm{Th}[/tex] = 232.038054 u
Mass of [tex]_{88}^{228}\textrm{Ra}[/tex] = 228.0301069 u
Mass of [tex]_{2}^{4}\textrm{He}[/tex] = 4.002602 u
To calculate the mass defect, we use the equation:
[tex]\Delta m=\text{Mass of reactants}-\text{Mass of products}[/tex]
Putting values in above equation, we get:
[tex]\Delta m=(m_{Th})-(m_{Ra}+m_{He})\\\\\Delta m=(232.038054)-(228.0301069+4.002602)=0.0053451u[/tex]
To calculate the energy released, we use the equation:
[tex]E=\Delta mc^2\\E=(0.0053451u)\times c^2[/tex]
[tex]E=(0.0053451u)\times (931.5MeV)[/tex] (Conversion factor: [tex]1u=931.5MeV/c^2[/tex] )
[tex]E=4.98MeV[/tex]
Hence, the energy released in the given nuclear reaction is 4.98 MeV.
When x-rays of wavelength 0.312 nm are directed at a crystalline sample, the smallest bragg angle for a certain family of reflecting planes is found to be 28.5°. within the sample, the atoms lie on a simple cubic lattice, a 2-dimensional view of which is shown to the right. assuming that the constructive interference observed is due to the pair of diagonal planes indicated by the two dashed lines, find the distance a between neighboring atoms?
light travels through a substance at 1.97x10^8. what is the index of the liquid?
The atmosphere _________ most of the incoming visual radiation.
A. Absorbs
B. Transmits
C. Reflects
Answer:
Absorbs
Explanation:
When the solar radiation or visual radiation arrives on Earth's atmosphere, most of the radiation is absorbed.
A part is reflected and transmitted back but major portion is absorbed by the atmosphere.
This absorb radiation helps to keep the Earth warm and thus maintaining the temperature even in Night time.
If a rock weighing 2,200 N is dropped from a height of 15 m, what is its KE just before it hits the ground? Remember, weight is measured in newtons (N), and is equal to mass times gravity.
A. 0 J
B. 2,224 J
C. 147 J
D. 33,000 J
You have just completed a wonderful meal of pasta and crusty bread followed by a huge piece of chocolate cake. This carbohydrate-rich meal has lead to the release of large amounts of sugar into your bloodstream. What is necessary to address the change in blood sugar level?
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
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 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 ?
Reflection is the bouncing of light rays off of a surface. Which situation is NOT an example of reflection?
A) looking at yourself in a mirror
B) focusing light through a camera lens
C) seeing an image of yourself in a still lake
D) looking at your teacher at the front of the class
The answer is B, Focusing light through a camera lens.s
Which change occurs when an atom undergoes decay?
lion and leopard are two of Africa's large cat ____.
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.
A battery is the power source for what type of current?
A. AC
B.BC
C.DC
D.All types of current
Answer:
C. DC
Explanation:
A battery is the power source for DC type of current. A battery is a source of constant potential difference that produces a constant current unlike in AC source where the voltage and hence the current changes its polarity continuously.Hence, the current produced by battery is direct current and not Alternating current.
Octane is an important component of gasoline. Octane will ignite at a temperature of 428°F. What is this temperature on the Celsius scale?
In the visible spectrum, red light has the lowest frequency and violet light has the highest. List the following colors in order of increasing energy. green blue yellow orange A) blue, green, yellow, orange B) orange, yellow, green, blue C) yellow, orange, blue, green D) green, blue, orange,w
The answer is b !!!!!!
Sonic boom from a plane is an example of a shockwave. Give another example where a shockwave is produced
What condition is necessary for a moving object to produce a shockwave?
A circuit has a current of 1.2 A. If the voltage decreases to one third of its original amount while the resistance remains constant, what will be the resulting current?
How much heat in joules is needed to vaporize an 18.0 gram sample of water at 100c?