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3 years ago

An atom emits a photon when one of its electrons:

Physics

1 answer:

disa [49]3 years ago

4 0

Answer:

undergoes a transition to a quantum state of lower energy

Explanation:

When electrons in an atom move to another quantum state, they emit/absorb a photon according to the following:

- If the electron is moving to a higher energy state, it absorbs a photon (because it needs energy to move to a higher energy level, so it must absorb the energy of the photon)

- if the electron is moving to a lower energy state, it emits a photon (because it releases the excess energy)

In particular, the energy of the absorbed/emitted photon is exactly equal to the difference in energy between the two levels of the electron transition:

$E=|E_1 - E_2|$

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joshua started cycling at 5:15pm. by 8:09 pm, he has covered a distance of 7250m. what was joshua's average speed during that ti

ser-zykov [4K]

Answer:

2,500m/h

Explanation:

Average speed is calculated as total speed traveled divide by total time taken:

$s_{avg}=\frac{d_{total}}{t_{total}}$

Given total distance as 7250m and total time as $2009-1715hrs= 2hrs \ 54min=2.9hrs$ , speed is calculated as :

$s_{avg}=\frac{d_{total}}{t_{total}}\\\\s_{avg}=\frac{7250m}{2.9hrs}\\\\=2500\ m/h$

Hence, Joshua's speed is 2,500m/h

8 0

3 years ago

Jack and Jill are maneuvering a 3100 kg boat near a dock. Initially the boat's position is < 2, 0, 3 > m and its speed is

liraira [26]

Answer:

(a) work done by Jack is -2200J

(b) work done by Jill is 0

Explanation:

Given;

Initially boat's position = < 2, 0, 3 > m

Final boat's position = < 6, 0, 1 > m

change in position = < 4, 0, -2 >

Force exerted by Jack = < -440, 0, 220 > N

Force exerted by Jill = < 170, 0, 340 > N

Part (a) How much work does Jack do?

work done = force x distance

Jack's work = < -440, 0, 220 > N x < 4, 0, -2 > m

= [(-440*4) + (0*0) + (220*-2)]

= -1760 J - 440 J

= -2200J

Part (b) How much work does Jill do?

Jill's work = < 170, 0, 340 > N x < 4, 0, -2> m

= [(170*4) + (0*0) + (340*-2)]

= 680 J - 680 J

= 0

7 0

4 years ago

Courtney wants to practice doing science. Which example best illustrates her

dybincka [34]

Answer:

Explanation:

because she wants to practice science and A is the practical option.

6 0

4 years ago

A cylindrically shaped piece of collagen (a substance found in the body in connective tissue) is being stretched by a force that

Marat540 [252]

Answer:

Part(a): The value of the spring constant is $3.11 \times 10^{2}~Kg~s^{-2}$ .

Part(b): The work done by the variable force that stretches the collagen is $1.5 \times 10^{-6}~J$ .

Explanation:

Part(a):

If ' $k$ ' be the force constant and if due the application of a force ' $F$ ' on the collagen ' $\Delta l$ ' be it's increase in length, then from Hook's law

$F = k~\Delta l....................................................................(I)$

Also, Young's modulus of a material is given by

$Y = \dfrac{F/A}{\Delta l/l}...............................................................(II)$

where ' $A$ ' is the area of the material and ' $l$ ' is the length.

Comparing equation ( $I$ ) and ( $II$ ) we can write

$&& Y = \dfrac{l~k}{A}\\&or,& k = \dfrac{Y~A}{l}\\&or,& k = \dfrac{Y~(\pi~r^{2})}{l}$

Here, we have to consider only the circular surface of the collagen as force is applied only perpendicular to this surface.

Substituting the given values in equation ( $III$ ), we have

$k = \dfrac{3.10 \times 10^{6}~N~m^{-2} \times \pi \times (0.00093)^{2}~m^{2}}{.027~m} = 3.11 \times 10^{2}~Kg~s^{-2}$

Part(b):

We know the amount of work done ( $W$ ) on the collagen is stored as a potential energy ( $U$ ) within it. Now, the amount of work done by the variable force that stretches the collagen can be written as