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3 years ago

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Make a sketch of the radius of gyration of a polymer chain vs. the degree of polymerization N as it would appear on a log-log sc

ale for: (a) a bad solvent, (b) a good solvent, and (c) a theta solvent. If the apparent log-log trend is linear, what is the significance of the slope?

1 answer:

zvonat [6]3 years ago

4 0

Answer:

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Explanation:

sjdnxjwodj1oeixjwkw9dijwqoisjd1

sjssusidej

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A 560-g squirrel with a surface area of 930cm2 falls from a 5.0-m tree to the ground. Estimate its terminal velocity. (Use a dra

bija089 [108]

Explanation:

Terminal velocity is given by:

$v_t=\sqrt{\frac{2mg}{\rho C_dA}}$

Here, m is the mass of the falling object, g is the gravitational acceleration, $C_d$ is the drag coefficient, $\rho$ is the fluid density through which the object is falling, and A is the projected area of the object. in this case the projected area is given by:

$A=\frac{A_s}{2}=\frac{930cm^2}{2}=465cm^2\\465cm^2*\frac{1m^2}{10^4cm^2}=0.0465m^2\\560g*\frac{1kg}{10^3g}=0.56kg$

Recall that drag coefficient for a horizontal skydiver is equal to 1 and air density is $1.28\frac{kg}{m^3}$ .

$v_t=\sqrt{\frac{2(0.56kg)(9.8\frac{m}{s^2})}{(1.28\frac{kg}{m^3}(1)(0.0465m^2)}}\\v_t=13.58\frac{m}{s}$

Without drag contribution the motion of the person is an uniformly accelerated motion, thus:

$v_f^2=v_o^2+2gh\\v_f=\sqrt{2gh}\\v_f=\sqrt{2(9.8\frac{m}{s^2})(5m)}\\v_f=9.9\frac{m}{s}$

7 0

3 years ago

A photon of wavelength 2.78 pm scatters at an angle of 147° from an initially stationary, unbound electron. What is the de Brogl

Elena-2011 [213]

Answer:

2.07 pm

Explanation:

The problem given here is the very well known Compton effect which is expressed as

$\lambda^{'}-\lambda=\frac{h}{m_e c}(1-cos\theta)$

here, $\lambda$ is the initial photon wavelength, $\lambda^{'}$ is the scattered photon wavelength, h is he Planck's constant, $m_e$ is the free electron mass, c is the velocity of light, $\theta$ is the angle of scattering.

Given that, the scattering angle is, $\theta=147^{\circ}$

Putting the respective values, we get

$\lambda^{'}-\lambda=\frac{6.626\times 10^{-34} }{9.11\times 10^{-31}\times 3\times 10^{8} } (1-cos147^\circ ) m\\\lambda^{'}-\lambda=2.42\times 10^{-12} (1-cos147^\circ ) m.\\\lambda^{'}-\lambda=2.42(1-cos147^\circ ) p.m.\\\lambda^{'}-\lambda=4.45 p.m.$

Here, the photon's incident wavelength is $\lamda=2.78pm$

Therefore,

$\lambda^{'}=2.78+4.45=7.23 pm$

From the conservation of momentum,

$\vec{P_\lambda}=\vec{P_{\lambda^{'}}}+\vec{P_e}$

where, $\vec{P_\lambda}$ is the initial photon momentum, $\vec{P_{\lambda^{'}}}$ is the final photon momentum and $\vec{P_e}$ is the scattered electron momentum.

Expanding the vector sum, we get

$P^2_{e}=P^2_{\lambda}+P^2_{\lambda^{'}}-2P_\lambda P_{\lambda^{'}}cos\theta$

Now expressing the momentum in terms of De-Broglie wavelength

$P=h/\lambda,$

and putting it in the above equation we get,

$\lambda_{e}=\frac{\lambda \lambda^{'}}{\sqrt{\lambda^{2}+\lambda^{2}_{'}-2\lambda \lambda^{'} cos\theta}}$

Therefore,

$\lambda_{e}=\frac{2.78\times 7.23}{\sqrt{2.78^{2}+7.23^{2}-2\times 2.78\times 7.23\times cos147^\circ }} pm\\\lambda_{e}=\frac{20.0994}{9.68} = 2.07 pm$

This is the de Broglie wavelength of the electron after scattering.

6 0

4 years ago

Si el número masico del elemento litio es 7 ¿cual es su nucleo?

sp2606 [1]

El núcleo tiene 3 protones (lo que le da al núcleo una carga de +3, identificándolo como el elemento Litio) y 4 neutrones (lo que le da un número total de masa de 7).

4 0

3 years ago

In a scale model of the Solar System, if the Sun is represented by a ball with a diameter of about 8 inches, about how large wou

Evgesh-ka [11]

Answer:

size of popcorn seed may meet the scaled earth size of x = 0.07312 in.

Explanation:

Given:-

- The diameter of actual sun, Ds = 1.3927 * 10^6 km

- The diameter of model sun ball, ds = 8 in

- The diameter of the actual earth, De = 12,742 km

Find:-

How large would be the earth model

Solution:-

- We can use the actual diameters of the earth and sun to develop the ratio of earth diameter to that of sun. The direct ratio can be used to model the diameter of earth for the scale model

Sun Earth

Actual : 1392700 km 12,742 km

Scale : 8 in x

- Use direct relations and solve for x:

x = (8 in)*(12,742 km ) / ( 1392700 km )

x = 0.07312 in.

- From the given options apple, grapefruit and marble diameters are larger than 1 inch. So only the size of popcorn seed may meet the scaled earth size of x = 0.07312 in.

4 0

3 years ago

Read 2 more answers

An object has an acceleration of 18.0 m/s/s. If the net force

Xelga [282]

Answer:

to ejam is god oh yum2

Explanation:

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3 years ago