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gayaneshka [121]
4 years ago
6

A simple cyanine dye molecule has a long central carbon chain, with a total of 8 bonds, between the two nitrogen atoms. One elec

tron per bond is essentially free to move up and down this chain. The potential energy for such an electron can be modeled as a one-dimensional box. The distance between each bond is about 0.14 nm.
What would be the transition corresponding to the lowest energy photon that this molecule could absorb? Would such a photon be in the visible range?
Physics
1 answer:
wariber [46]4 years ago
4 0

Answer:

For one dimensional box

E= n^{2}h^{2}/ 8mL^{2}

For lowest energy transition will be from n =1 to n=2

Hence,

hc/\lambda = 2^{2}h^{2}/ 8mL^{2} - h^{2}/8mL^{2}

h= 6.626 *10-34 J.s

m = 9.31 *10-31 Kg

L= 0.14 * 10-9 m

c= 3 *108 m/s

\lambda = 8*c*m*L^{2} / 3*h

\lambda = 22 nm

Not in visible range

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An alpha particle (a He nucleus, containing two protons and two neutrons and having a mass of 6.64×10−27 kg ) traveling horizont
victus00 [196]

Answer:

A) d = 1.38 10-3 m, B)   the velocity modulus remains constant and the velocity direction changes since the force is perpendicular

c)  a  = 1.94 10¹² m / s

d) the force is perpendicular to these two, that is, it points out of the page (positive z-axis)

e) E) the modulus of velocity remains constant because the force is perpendicular to the movement,

Explanation:

A)  Let's use Newton's second law for this problem where the force is the magnetic force given by

            F = m a

The magnetic force is

          F = q v x B = q v B sin θ

Where the angle between the speed and the magnetite field is ce 90º so the sin 90 = 1

This implies that the acceleration is centripetal, which is given by

           a = v² / R

We substitute

          q v B = m v² / r

          r = m v / qB

 Let's calculate

         r = 6.64 10⁻²⁷ 36.6 10³ / (2 1.6 10⁻¹⁹  1.10)

         r = 6,904 10⁻⁴ m

Diameter is twice the radius

          d = 2 r

          d= 1.38 10-3 m

B) The effect of the magnetic field is that the particle describes a circular motion, where the velocity modulus remains constant and the velocity direction changes since the force is perpendicular

C) the centripetal acceleration is

           F = m a

           q v B = m a

           a = q v B / m

Let's calculate

           a = 2  1.6 10⁻¹⁹ 36.6 10³ 1.10 / 6.64 10⁻²⁷

           a  = 1.94 10¹² m / s

D) Acceleration has the same direction of force toward the center of the circular orbit,

If we assume that the horizontal direction of the alpha particle is on the x-axis, the field is on the positive y-axis, so the force is perpendicular to these two, that is, it points out of the page (positive z-axis)

E) the modulus of velocity remains constant because the force is perpendicular to the movement, but the direction of the velocity does change in the direction of the force

6 0
3 years ago
How many neutrons does an atom of Dubnium have in its nucleus
attashe74 [19]
Dubnium is a synthetic element ... Number 105.  It can be created
in a laboratory but it's not found in nature.

Fifteen (15) different isotopes of Dubnium have been created.  They all
have 105 protons in the nucleus of every atom, but they have anywhere
from 256 to 270 neutrons in each nucleus.

The most stable isotope of Dubnium is  ²⁶⁸Db , with 163 neutrons in the
nucleus.  That form of Dubnium atom has a 50-50 chance of surviving
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5 0
3 years ago
A "seconds pendulum" is one that moves through its equilibrium position once each second. (The period of the pendulum is precise
Alex73 [517]
<h2>Ratio of free fall acceleration of Tokyo to Cambridge = 0.998</h2>

Explanation:

We know the equation

            T=2\pi \sqrt{\frac{l}{g}}

   where l is length of pendulum, g is acceleration due to gravity and T is period.

Rearranging

              g= \frac{4\pi^2l}{T^2}

Length of pendulum in Tokyo = 0.9923 m

Length of pendulum in Cambridge = 0.9941 m

Period of pendulum in Tokyo = Period of pendulum in Cambridge = 2s

We have

                     \frac{ g_{\texttt{Tokyo}}}{ g_{\texttt{Cambridge}}}= \frac{\frac{4\pi^2 l_{\texttt{Tokyo}}}{ T_{\texttt{Tokyo}}^2}}{\frac{4\pi^2 l_{\texttt{Cambridge}}}{ T_{\texttt{Cambridge}}^2}}\\\\\frac{ g_{\texttt{Tokyo}}}{ g_{\texttt{Cambridge}}}=\frac{\frac{0.9923}{2^2}}{\frac{0.9941}{2^2}}=0.998

Ratio of free fall acceleration of Tokyo to Cambridge = 0.998

6 0
3 years ago
An object slides on a level surface in the +x direction. It slows and comes to a stop with a constant acceleration of -2.45 m/s2
Stolb23 [73]

Answer:

uk = 0.25

Explanation:

Given:-

- An object comes to stop with acceleration, a = -2.45 m/s^2

Find:-

What is the coefficient of kinetic friction between the object and the floor?

Solution:-

- Assuming the object has mass (m) that slides over a rough surface with coefficient of kinetic friction (uk). There is only Frictional force (Ff) acting in the horizontal axis on the object opposing the motion (-x direction).

- We will apply equilibrium equation on the object in vertical direction.

                               N - m*g = 0

                               N = m*g

Where,  N : Contact force exerted by the surface on the floor

             g : Gravitational acceleration constant = 9.81 m/s^2

- Now apply Newton's second law of motion in the horizontal ( x-direction ):

                             - Ff = m*a

- The frictional force is related to contact force (N) by the following expression:

                              Ff = uk*N

- Substitute the 1st and 3rd expressions in the 2nd equation:

                             uk*m*g = -m*a

                             uk = a / g

- Plug in the values and solve for uk:

                             uk = - (-2.45) / 9.81

                             uk = 0.25        

8 0
3 years ago
DUEEEE IN 3 HOURS!!
kakasveta [241]

Answer:

air humidity

Explanation:

Air parcel is a blob of air which moves in the atmosphere. For stability, if the air parcel is displaced vertically then it returns to the original position.

The most important points to know of the rising air parcel are the air humidity of the air, the temperature of the air and its dew point. These are the critical information to determine the stability of the air.

The air parcel rises buoyantly as it gets warmer than the surrounding environment.

7 0
3 years ago
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