Answer:
The initial and final states of the hydrogen atom were n=2 and n=6 respectively.
Explanation:
We must first obtain the energy of the photon;
E= hc/λ
where;
h= Plank's constant = 6.6 * 10^-34 JS
c= speed of light = 3* 10^8 m/s
λ = wavelength of light= 411 nm = 411* 10^-9 m
Substituting values;
E = 6.6 * 10^-34 * 3* 10^8 / 411* 10^-9
E = 4.8 * 10^-19 J or 3.0 eV
But ;
En = 13.6/n^2
So E = En final - En initial
3.0 = -13.6(1/n^2final - 1/n^2initial)
If we substitute n^2final = 6 and n^2 initial = 2 then the RHS becomes approximately equal to the LHS
Therefore the initial and final states of the hydrogen atom were n=2 and n=6 respectively.
A person picking apples stand on a ladder 3.0 m above the ground. He throws them into
a basket 2.0 m away. How fast must the person throw the apple in order for it to land in
the basket?
Answer:
The speed the apple must be thrown in order for it to land in the basket is 2.554 m/s.
Explanation:
Given;
height above the ground, h = 3.0 m
horizontal distance, X = 2.0 m
The time to drop from the given height;
h = ¹/₂gt²
[tex]t = \sqrt{\frac{2h}{g} }\\\\t = \sqrt{\frac{2*3}{9.8} }\\\\t = 0.783 \ s[/tex]
The horizontal speed traveled by the apple is given by;
vₓ = X / t
vₓ = 2 / 0.783
vₓ = 2.554 m/s
Therefore, the speed the apple must be thrown in order for it to land in the basket is 2.554 m/s.
80g of kerosene was burned to raise the temperature of 3 l of water to 90c ⁰C. What is the efficiency of the burner?
Answer:
363
Explanation:
80g of kerosene was burned to raise the temperature
k = 90+273
= 363
A light bulb uses 1.2 A when connected across a 120 V source. What is the resistance by the bulb?
In 1926 Babe Ruth hit a home run that was estimated to have landed 180. meters from home plate and to have reached a height of 21.3 meters. What was the initial velocity of the ball?
Answer:
v = 47.85 m / s , θ = 64.7º
Explanation:
This is a missile throwing exercise.
Let's find the speed to reach the maximum height, at this point the vertical speed is zero
[tex]v_{y}^{2}[/tex] = v_{oy}^{2} - 2 g y
0 = v_{oy}^{2} - 2gy
v_{oy} = √2gy
let's calculate
v_{oy} = √ (2 9.8 21.3)
v_{oy} = 20.43 m / s
now we can calculate the time it takes to get to this point
vy = v_{oy} - g t
t = v_{oy} / g
t = 20.43 / 9.8
t = 2.08 s
in projectile launching, the time it takes for the body to rise is the same as the time it takes to go down, so the total launch time is
[tex]t_{v}[/tex] = 2 t
t_{v} = 2 2.08 = 4.16 s
let's use the horizontal throw ratio
x = v₀ₓ t_{v}
v₀ₓ = x / t_{v}
v₀ₓ = 180 / 4.16
v₀ₓ = 43.27 m / s
initial velocity is
v = √ (v₀ₓ² + v_{oy}^{2})
v = √ (20.43² + 43.27²)
v = 47.85 m / s
with an angle of
tan θ = I go / vox
θ = tan⁻¹ (43.27 / 20.43)
θ = 64.7º
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Answer:
ok
Explanation:
what are fundamental quantities
Answer: length, luminous intensity,mass, time, temperature, electric current, amount of a substance.
Explanation:
Astronomers discover a bright X-ray source in the Milky Way. They see no counterpart in the optical bands, but it has another star orbiting it, and they determine that the X-ray source has a mass of 10 MSun. What is the most likely origin of the X-rays?
a. a black hole
b. a neutron star
c. a white dwarf
d. a gamma-ray burst
Answer:
a. a black hole
Explanation:
X-ray emission from the central degrees of the Milky Way Bright X-ray emission traces the coherent edge brightened shell-like feature, dubbed the northern chimney, located north of Sgr A* and characterized by a diameter of about 160 pc. On the opposite side, the southern chimney appears as a bright linear feature. Bright X-ray emission is observed at high latitude
Calculate the pressure in pascals if a 560N is applied to an area of 1.6m².
Answer:
P = 350 [Pa]
Explanation:
The pressure is calculated by knowing the force and area. By means of the following formula can be calculated by means of the following equation.
Units of 1 [Pa] = 1 [N/m²]
P = F/A
where:
P = pressure [Pa]
F = force = 560 [N]
A = area = 1.6 [m²]
P = 560/1.6
P = 350 [Pa]
At the focal point of a converging lens, the object cannot be seen. O A. True B. False
Answer: True
Explanation: Guessed on A p E x and it was correct
Answer:
True
Explanation:
a p e x
find the mass of an object with a density of 1.5 g/cm^3 and had a volume of 8cm^3
Answer:
12 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 1.5 × 8
We have the final answer as
12 gHope this helps you
One particle has mass m and a second particle has mass 2m. The second particle is moving with speed v and the first with speed 2v. How do their kinetic energies compare?
Answer:
Explanation:
The formula for kinetic energy to be used here is 1/2mv².
If the first particle is "particle a" and the second particle is "particle n"; there kinetic energies (K.E) will be
K.Eₐ = 1/2.m2v² = mv²
K.Eₙ = 1/2.2mv² = mv²
From the above, it can be said that there kinetic energies are the same.
NOTE that the m and v used in the question means mass and velocity respectively.
People have been able to make materials such as fiber optics cables A. using nails and screws. B. using glue and scissors. C. using rocks and stones. D. using science and technology.
Answer:
D
Explanation:
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.
please help im failing!!!
Freida wants to model the way atoms move when a substance changes its state. To do this, Freida makes a pyramid of marshmallows. Then, she knocked down the pyramid causing the marshmallows to fall. If the marshmallows represent the atoms in the substance, which change of state is Freida modeling?
Answer:melting 2020 edge
Explanation:
:)
Answer:
Melting
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]
Make a rule: How does the energy needed to move an electron to a higher energy level compare to the energy emitted when the electron moves back to the lower energy level
Answer:
Explanation:
Generally, the energy required to move an electron from one energy level to another energy level is referred to as quantum energy. An atom will absorb energy when it's electron(s) move from a lower energy level (ground state) to a higher energy level (excited state) and will emit energy when it's electron(s) move from a higher energy level to a lower energy level.
Since, electrons do not stay in the excited state forever, they indeed prefer the ground state and thus will always return to the ground state. When an electron thus return to the ground state, it sheds off the excess energy that took it to the excited state thus it can be said that more energy is required to take an electron to it's excited state.
Answer:
Explanation:
When an atom absorbs energy it will go up x number levels. When it admits energy it will go down to its previous energy level and emit the same exact amount of energy that was absorbed.
A particle with charge q and mass m moving with speed v in the x direction enters a magnetic field of strength B pointing in the y direction. The magnitude of the acceleration of the particle as it travels one semicircle is
Answer:
The acceleration of the particle as it travels one semicircle is
[tex]a= \frac{\pi R}{t^2}[/tex]
Explanation:'
Kindly see attached a sketch of a semi-circle
Step one:
given data
velocity =v
let the time taken be t
The path PQM is the distance covered
so distance [tex]d= \pi R[/tex]
we know that time= distance/velocity
t= πR/v
step two:
velocity =distance/time
[tex]velocity=\frac{\pi R}{t}[/tex]
also, we know that acceleration is velocity/time
[tex]a= \frac{\pi R}{\frac{t}{t} }[/tex]
[tex]a= \frac{\pi R}{t}*\frac{1}{t}[/tex]
[tex]a= \frac{\pi R}{t^2}[/tex]
Why would a baseball traveling at 20 m/s have more kinetic energy than a baseball traveling at 5 m/s?
Answer:
because formula of kinetic energy is K=1/2mv^2 that means more the velocity then more kinetic energy
Upon being struck by 240-nm photons, a metal ejects electrons with a maximum kinetic energy of 2.97 eV. What is the work function of this metal?
Answer:
Work Function = 3.53 x 10⁻¹⁹ J = 2.2 eV
Explanation:
The work function of the metal metal can be found as follows:
Energy of Photon = Work Function + K.E
hc/λ = Work Function + K.E
Work Function = hc/λ - K.E
where,
h = Plank's Constant = 6.625 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of photons = 240 nm = 2.4 x 10⁻⁷ m
K.E = Maximum Kinetic Energy = (2.97 eV)(1.6 x 10⁻¹⁹ J/1 eV) = 4.752 x 10⁻¹⁹ J
Therefore,
Work Function = (6.625 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(2.4 x 10⁻⁷ m) - 4.752 x 10⁻¹⁹ J
Work Function = 8.281 x 10⁻¹⁹ J - 4.752 x 10⁻¹⁹ J
Work Function = 3.53 x 10⁻¹⁹ J = 2.2 eV
A wagon wheel consists of 8 spokes of uniform diamter, each of mass m, and length L. The outer ring has a mass m rin. What is the moment of inertia of the wheel through an axis through the center and perpendicular to the plane of the ring? Assume that each spoke extends from the center to the outer ring is of negligible thickness.
Answer:
[tex]L^2(\dfrac{8m}{3}+m_r)[/tex]
Explanation:
m = Mass of each rod
L = Length of rod = Radius of ring
[tex]m_r[/tex] = Mass of ring
Moment of inertia of a spoke
[tex]\dfrac{mL^2}{3}[/tex]
For 8 spokes
[tex]8\dfrac{mL^2}{3}[/tex]
Moment of inertia of ring
[tex]m_rL^2[/tex]
Total moment of inertia
[tex]8\dfrac{mL^2}{3}+m_rL^2\\\Rightarrow L^2(\dfrac{8m}{3}+m_r)[/tex]
The moment of inertia of the wheel through an axis through the center and perpendicular to the plane of the ring is [tex]L^2(\dfrac{8m}{3}+m_r)[/tex].
If the resistance in the coil is 2.0 , what is the magnitude of the induced current in the coil while the field is changing
This question is incomplete, the complete question is;
A coil consists of 200 turns of wire. Each turn is a square of side 18 cm, and a uniform magnetic field directed perpendicular to the plane of the coil is turned on. If the field changes linearly from 0 to 0.50 T in 0.80 s,
a) what is the magnitude of the induced emf in the coil while the field is changing?
b) if the resistance of the coil is 2.0, what is the magnitude of the induced current in the coil while the field is changing?
Answer:
a) the magnitude of the induced emf in the coil is 4.05 V
b) induced current in the coil I is 2.025 A
Explanation:
Given that;
side of turn a = 18 cm = 0.18 m
no. of turns N = 200
dB = 0.50 T
time t = 0.80 sec
(a)
what is the magnitude of the induced emf in the coil while the field is changing?
we know that the magnetic flux is equal to the product of the magnetic field in a loop and the area of the loop so;
∅ = NBA
expression for the electromotive force is expressed as;
∈ = d∅/dt
Now replace NBA for ∅ in the above equation.
∈ = d(NBA) / dt
= NA(dB/dt)
The expression for the area of each square turn is expressed as follows
A = a²
a is the side of the turn
so we substitute the value of a
A = (0.18) ²
A= 0.0324 m²
As earlier derived
formula for the electromotive force is as follows:
∈ = NA(dB/dt)
so we substitute all our values
∈ = (200)(0.0324m²) (0.50T/0.80s)
∈ = 6.48 × 0.625
∈ = 4.05 V
Therefore the magnitude of the induced emf in the coil is 4.05 V
(b)
if the resistance of the coil is 2.0, what is the magnitude of the induced current in the coil while the field is changing?
we know that the current induced in the circuit is equal to the ratio between the electromotive forces to the resistance of the ring so;
I = ∈ / R
given that; resistance of the coil = 2.0
so we substitute
I = 4.05 / 2.0
I = 2.025 A
Therefore induced current in the coil I is 2.025 A
Please select the word from the list that best fits the definition The skeletons of tiny ocean animals grow together to form ______, structures that are found only in warm, clear ocean water.
Answer:
coral reef
Explanation:
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
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.
Learn more about the biodata here:
https://brainly.com/question/22965812
5)
Using only the information available in the periodic table, consider the elements calcium and chlorine. From their
location on the periodic table, identify the oxidation state and number of valence electrons for calcium and chlorine.
Which statement most accurately describes the compound formed by calcium and chlorine?
C
A)
B)
Calcium, a nonmetal with an oxidation number of +2 will form a covalent
bond with chlorine, a halogen (nonmetal) with an oxidation number of -1
called calcium chloride (CaCl2).
Calcium, an alkaline earth metal with an oxidation number of +2 will form
covalent bond with chlorine, also a metal with an oxidation number of -1
called calcium dichloride (CaCla)
Calcium, an alkaline earth metal with an oxidation number of +2 will form
an ionic bond with chlorine, a halogen in group VILA with an oxidation
number of -1 called calcium chloride (CaCl2).
Calcium, an alkaline earth metal with an oxidation number of 2 will share
electrons to form an lonic bond with chlorine, a nonmetal with an
xidation number of -1 called calcium dichloride (CaCl).
D)
Answer:C,(Calcium,an alkaline earth metal with an oxidation number of +2 will form an ionic bond with chlorine,a halogen in group VllA with an oxidation number of -1 called calcium chloride (CaCl2)
Explanation:
on USAtestprep !!
Calcium, an alkaline earth metal with an oxidation number of +2 will form
an ionic bond with chlorine, a halogen in group VIIA with an oxidation
number of -1 called calcium chloride (CaCl₂). This is correct statement.
What is oxidation number?Simply said, the number assigned to each element in a chemical combination is the definition of an oxidation number. The total number of electrons that an atom in a molecule can share, lose, or gain while forming a chemical bond with an atom of a different element is known as the oxidation number.
Also known as oxidation state, oxidation number is a numerical value. But depending on whether we take into account the atoms' electronegativity or not, these phrases might occasionally have a different meaning. In coordination chemistry, the term "oxidation number" is often used.
According to Periodic table: calcium is a alkaline earth metal with an oxidation number of +2 whereas chlorine is a halogen in group VIIA with an oxidation number of -1. When they reacts chemically, they form an ionic compound named calcium chloride having chemical formula CaCl₂.
Learn more about oxidation number here:
https://brainly.com/question/29100691
#SPJ2
What kind of energy do electric and magnetic fields contain?
A
thermal energy
B
electrical energy
C
kinetic energy
D
pot
Answer:
Electromagnetic waves
Electromagnetic waves bring energy into a system by virtue of their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. However, there is energy in an electromagnetic wave itself, whether it is absorbed or not.
So the answer is B electrical energy
Thank you and please rate me as brainliest as it will help me to level up
During a medieval siege of a castle, the attacking army uses a trebuchet to hurl heavy stones at the castle walls. If the trebuchet launches the stones with a velocity of +48.5" m"/s at an angle of 42.0°, how long does it take the stone to hit the ground? For those settings, what is the maximum range? How high will the stones go? Show all your work
Answer:
a) t = 6.62 s
b) x = 238.6 m
c) H = 53.7 m
Explanation:
a) We can find the time of flight as follows:
[tex] y_{f} = y_{0} + v_{0_{y}}t - \frac{1}{2}gt^{2} [/tex]
Where:
[tex]y_{f}[/tex] is the final height = 0
[tex]y_{0}[/tex] is the initial height = 0
[tex]v_{0_{y}}[/tex] is the initial vertical velocity of the stone
t: is the time
g: is the gravity = 9.81 m/s²
[tex] v_{0}sin(42)t - \frac{1}{2}gt^{2} = 0 [/tex]
[tex] 48.5 m/s*sin(42)*t - \frac{1}{2}9.81 m/s^{2}*t^{2} = 0 [/tex]
By solving the above quadratic equation we have:
t = 6.62 s
b) The maximum range is:
[tex] x = v_{0_{x}}t = 48.5 m/s*cos(42)*6.62 s = 238.6 m [/tex]
c) The maximum height (H) can be found knowing that at this height the final vertical velocity of the stone is zero:
[tex] v_{f_{y}}^{2} = v_{0_{y}}^{2} - 2gH [/tex]
[tex] H = \frac{v_{0_{y}}^{2} - v_{f_{y}}^{2}}{2g} = \frac{(48.5 m/s*sin(42))^{2} - 0}{2*9.81 m/s^{2}} = 53.7 m [/tex]
I hope it helps you!
To remove a stain using a solvent the stain has to become dissolved in the solvent
True
False
Answer:
True
Explanation:
have a good day:)
Answer: This statement is True
A force of 29.4 N is required to pull a 100 kg ice block at constant speed along an ice surface. Find the coefficient of kinetic friction for ice on ice.
Answer:
The value is [tex]\mu_k = 0.03[/tex]
Explanation:
From the question we are told that
The force applied on the ice is [tex]F = 29.4 N[/tex]
The mass of the ice block is [tex]m = 100 \ kg[/tex]
Generally for the ice block to move at constant speed , the force applied on it must be equal to the kinetic frictional force which is mathematically represented as
[tex]F_F = m* g * \mu_k[/tex]
=> [tex]F = F_F = m* g * \mu_k[/tex]
=> [tex]29.4 = 100 * 9.8 * \mu_k[/tex]
=> [tex]\mu_k = 0.03[/tex]