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2 years ago

Visual aids are useful for all of the following reasons except

Engineering

1 answer:

Ksivusya [100]2 years ago

4 0

Answer:

Explanation:

their presence allows the speaker to take a rest from talking

I couldnt see the question

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Very thin films are usually deposited under vacuum conditions to prevent contamination and ensure that atoms can fly directly fr

katrin [286]

Answer:

a. 9947 m

b. 99476 times

c. 2*10^11 molecules

Explanation:

a) To find the mean free path of the air molecules you use the following formula:

$\lambda=\frac{RT}{\sqrt{2}\pi d^2N_AP}$

R: ideal gas constant = 8.3144 Pam^3/mol K

P: pressure = 1.5*10^{-6} Pa

T: temperature = 300K

N_A: Avogadros' constant = 2.022*10^{23}molecules/mol

d: diameter of the particle = 0.25nm=0.25*10^-9m

By replacing all these values you obtain:

$\lambda=\frac{(8.3144 Pa m^3/mol K)(300K)}{\sqrt{2}\pi (0.25*10^{-9}m)^2(6.02*10^{23})(1.5*10^{-6}Pa)}=9947.62m$

b) If we assume that the molecule, at the average, is at the center of the chamber, the times the molecule will collide is:

$n_{collision}=\frac{9947.62m}{0.05m}\approx198952\ times$

c) By using the equation of the ideal gases you obtain:

$PV=NRT\\\\N=\frac{PV}{RT}=\frac{(1.5*10^{-6}Pa)(\frac{4}{3}\pi(0.05m)^3)}{(8.3144Pa\ m^3/mol\ K)(300K)}=3.14*10^{-13}mol\\\\n=(3.14*10^{-13})(6.02*10^{23})\ molecules\approx2*10^{11}\ molecules$

5 0

3 years ago

A plumbed eyewash station is portable.

Hitman42 [59]

Plumbed stations are permanently connected to a source of potable water, whereas portable stations are self-contained gravity-fed units with their own flushing fluid that must be replaced after each use. ... Eyewash fluid must irrigate and flush both eyes simultaneously.
Hopefully this helped.

8 0

3 years ago

The fracture strength of glass may be increased by etching away a thin surface layer. It is believed that the etching may alter

UkoKoshka [18]

Maybe it willl be I don’t know

7 0

2 years ago

A gas flows through a one-inlet, one-exit control volume operating at steady state. Considering an adiabatic control volume with

Hunter-Best [27]

Answer:

b. equal to the specific entropy of the gas at the inlet.

Explanation:

Isentropic process is the process in which the entropy of the system remains unchanged. The word isentropic is formed from the combination of the prefix "iso" which means "equal" and the word entropy.

If a process is completely reversible, without the need to provide energy in the form of heat, then the process is isentropic.

3 0

3 years ago

What are the four causes of electrical faults?

Arada [10]

Answer:

Electrical faults are also caused due to human errors such as selecting improper rating of equipment or devices, forgetting metallic or electrical conducting parts after servicing or maintenance, switching the circuit while it is under servicing, etc.

Explanation:

6 0

3 years ago