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2 years ago

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What is the explanation for how a modern transmission electron microscope (TEM) can achieve a resolution of about 0.2 nanometers

, whereas a standard light microscope has a maximum resolution of about 200 nanometers?

1 answer:

IgorC [24]2 years ago

3 0

Answer:

Explanation:

A simple light microscope uses light for imaging of objects where as a transmission electron microscope uses a monochromatic beam of electrons.

This beam is passed by a magnetic field which is very strong and thus act as a lens.

Its resolution of very high which is about 0.2 nanometers because of the separation between two atoms.

Because of this reason its resolution is about 1000 times greater than light microscope.

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Water evaporating from a pond does so as if it were diffusing across an air film 0.15 cm thick. The diffusion coefficient of wat

QveST [7]

Answer:

The water level will drop by about 1.24 cm in 1 day.

Explanation:

Here Mass flux of water vapour is given as

$j_{H_2O}=\frac{D}{l} \bigtriangleup c$

where

$j_{H_2O}$ is the mass flux of the water which is to be calculated.

D is diffusion coefficient which is given as $0.25 cm^2/s$

l is the thickness of the film which is 0.15 cm thick.
$\bigtriangleup c$ is given as

$\bigtriangleup c= \frac{P_{sat}-P_a}{RT}$

In this

$P_{sat}$ is the saturated water pressure, which is look up from the saturated water property at 20°C and 0.5 saturation given as 2.34 Pa

$P_a$ is the air pressure which is given as 0.5 times of $P_{sat}$

R is the universal gas constant as $8.314 kJ/kmol-K$

T is the temperature in Kelvin scale which is $20+273= 293K$

By substituting values in the equation

$\bigtriangleup c= \frac{P_{sat}-P_a}{RT} \\ \bigtriangleup c= \frac{P_{sat}-0.5P_{sat}}{RT} \\ \bigtriangleup c= \frac{0.5P_{sat}}{RT} \\ \bigtriangleup c= \frac{0.5 \times 2.34}{8.314 \times 293} \\\bigtriangleup c= 0.48 mol/m^3$

Converting $\bigtriangleup c$ into $cm^3/cm^3$

As 1 mole of water 18 $cm^3$ so

$\bigtriangleup c= 0.48 mol/m^3 \\ \bigtriangleup c= 0.48 \times 18 \times 10^{-6} cm^3/cm^3 \\ \bigtriangleup c= 8.64 \times 10^{-6} cm^3/cm^3$

Putting this in the equation of mass flux equation gives

$j_{H_2O}=\frac{D}{l} \bigtriangleup c \\ j_{H_2O}=\frac{0.25}{0.15} \times 8.64 \times 10^{-6} \\ j_{H_2O}=14.4 \times 10^{-6} cm/s$

For calculation of water level drop in a day, converting mass flux as

$j_{H_2O}=14.4 \times 10^{-6} \times 24 \times 3600 cm/day\\ j_{H_2O}=1.24 cm/day$

So the water level will drop by about 1.24 cm in 1 day.

7 0

2 years ago

A man in a strength competition pulls an 18-wheel truck 3.10 m in 20.5 s. There is a cable that is attached to his body that exe

larisa [96]

Answer:

114.32195122 but Round your answer to three significant figures.) is 114

Explanation:

Just took the test

4 0

2 years ago

There are two forces on the 2 kg box in the overhead view of the following figure, but only one is shown. For F1=20N, a= 12 m/s2

maw [93]

Answer:

second force = 32.784

Magnitude = $\sqrt{32.784$

θ = -90°

Explanation:

a)

Fnet = ma

F1 + F2 = ma

20N + F2 = 2(12 × cos30° + 12 ×sin30°)

F2 = 2 × 12 ( sin 30° + cos 30°)

= 24 × ( 1 + √3 )÷ 2

=12 (1 +√3 )

= 32.784

b) $\sqrt{12(1 +\sqrt{3}}$

= $\sqrt{12 ( 1+ 1.732)}$

= $\sqrt{12 (2.732)}$

= $\sqrt{32.784}$

c)

θ = 30° + 180°

θ = 210°

210° - 300°

θ = -90°

8 0

2 years ago

The chemical formula for water, H2O, means that each water molecule contains

Ainat [17]

The chemical formula for water, H2o means that each water molecule contains one oxygen atom and two hydrogen atoms. This is the formula for water which has a liquid form, a solid form as ice, and also a gaseous form as water vapor.

5 0

2 years ago

Read 2 more answers

A machine part is vibrating along the x-axis in simple harmonic motion with a period of 0.27 s and a range (from the maximum in

Gnoma [55]

Answer:

$x = -1.437 cm$

Explanation:

The general equation for position of Simple harmonic motion is given as:

$x = A sin(\omega t)$ ........(1)

where,

x = Position of the wave

A = Amplitude of the wave

ω = Angular velocity

t = time

In this case, the amplitude is just half the range,

thus,

$A =\frac{3cm}{2}=1.5cm$ (Given range = 3cm)

A = 1.5 cm

Now, The angular velocity is given as:

$\omega=\frac{2\pi}{T}$

Where, T = time period of the wave =0.27s (given)

$\omega=\frac{2\pi}{0.27s}$

or

$\omega=23.27s^{-1}$

so, at time t = 55 s, the equation (1) becomes as:

$x = 1.5 sin(23.27\times 55)$

on solving the above equation we get,

$x = -1.437 cm$

here the negative sign depicts the position in the opposite direction of +x

5 0

2 years ago