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4 years ago

14

An electromagnetic wave with high frequency and high energy is A. Safe for humans. B. Is helpful to humans. C. Is helpful to hum

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1 answer:

Vilka [71]4 years ago

4 0

B and C are both correct choices.

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What region of the atom determines the volume of the atom

NeX [460]

Hello kiddio!

Most of the mass<span> of atom is in a dense positively charged </span>nucleus<span>. Most of the volume of an atom is in an empty space in which negatively charged electrons move around the </span>nucleus<span>.
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3 0

4 years ago

A shield of material that reflects neutrons is placed around a radioactive sample. Which change in the nuclear reaction is most

Crazy boy [7]

Answer:

A chain reaction will be sustained in a sub-critical mass.

Explanation:

Hope this helps!

If not, I am sorry.

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2 years ago

A space station, in the form of a wheel 140 m in diameter, rotates to provide an "artificial gravity" of 3.90 m/s2 for persons w

Zigmanuir [339]

Radial acceleration is given by

$a_{rad}= \frac{v^2}{r}$
where

$v=r \omega$
then

$a_{rad}= \frac{r^2 \omega^2}{r}=r\omega^2$

Now

$70\omega^2=3.90 \frac{m}{s^2} \\ \\ \omega= \sqrt{ \frac{3.9}{70} }$

Using the relation

$\omega=2 \pi f$

$2 \pi f= \sqrt{ \frac{3.9}{70} }\\ \\ f= \frac{1}{2 \pi}\sqrt{ \frac{3.9}{70} }Hz$

Putting into rpm

$\frac{60}{2 \pi}\sqrt{ \frac{3.9}{70}} =2.254rpm$

8 0

4 years ago

Materials will have different energies associated with the electrons inside them. This is related to how strongly bound they are

andrey2020 [161]

Answer:

E = 401.3 eV

Explanation:

As we know that the thinnest gap in the direction of metal is given as

$t = 3.09 nm$

so here we can say that lowest energy of photon will not able to break this electron from above thickness

so we will have

$E = \frac{hc}{\lambda}$

here we have

$hc = 1240 nm-eV}$

also we have

$\lambda = 3.09 nm$

so we will have

$E = \frac{1240}{3.09} eV$

$E = 401.3 eV$

7 0

4 years ago

The group one metals are called alkaline metal and group two metals are called alkaline earth metal why?

Ilya [14]

Answer:

The group one element are called alkali because when they dissolved in water they form alkaline solutions

5 0

2 years ago