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3 years ago

What is the mass number of an atom with five protons and seven neutrons

Physics

1 answer:

SVEN [57.7K]3 years ago

8 0

Answer:

Explanation:

The number of electrons in an atom is always the same as the number of protons, so atoms are electrically neutral overall.

Atoms can lose or gain electrons. When they do, they form charged particles called ions:

if an atom loses one or more electrons, it becomes a positively charged ion

if an atom gains one or more electrons, it becomes a negatively charged ion

Hope this helps

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The range of all electromagnetic radiation is known as the

Readme [11.4K]

B.) <span>The range of all electromagnetic radiation is known as the "Electromagnetic Spectrum"

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6 0

3 years ago

The critical angle for a special type of glass in air is 30.8 ◦ . the index of refraction for water is 1.33. what is the critica

Alina [70]

When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted light, and all the light is reflected. The value of this angle is given by
$\theta_c = \arcsin ( \frac{n_2}{n_1} )$
where n2 and n1 are the refractive indices of the second and first medium, respectively.

In the first part of the problem, light moves from glass to air ( $n_a=1.00$ ) and the critical angle is $\theta_c = 30.8^{\circ}$ . This means that we can find the refractive index of glass by re-arranging the previous formula:
$n_g=n_1 = \frac{n_2}{\sin \theta_c}= \frac{1.00}{\sin 30.8^{\circ}}=1.95$

Now the glass is put into water, whose refractive index is $n_w = 1.33$ . If light moves from glass to water, the new critical angle will be
$\theta_c = \arcsin ( \frac{n_2}{n_1} )=\arcsin( \frac{n_w}{n_g} )=\arcsin( \frac{1.33}{1.95} )=\arcsin(0.68)=43.0^{\circ}$

6 0

3 years ago

Any help is appreciated please

stiv31 [10]

Answer:

C. It speeds up, and the angle increases

Explanation:

We can answer by using the Snell's law:

$n_i sin \theta_i = n_r sin \theta_r$

where

$n_i, n_r$ are the refractive index of the first and second medium

$\theta_i$ is the angle of incidence (measured between the incident ray and the normal to the surface)

$\theta_r$ is the angle of refraction (measured between the refracted ray and the normal to the surface)

In this problem, light moves into a medium that has lower index of refraction, so

$n_r < n_i$

We can rewrite Snell's law as

$sin \theta_r =\frac{n_i}{n_r}sin \theta_i$

and since

$\frac{n_i}{n_r}>1$

this means that

$sin \theta_r > sin \theta_i$

which implies

$\theta_r > \theta_i$

so, the angle increases.

Also, the speed of light in a medium is given by

$v=\frac{c}{n}$

where c is the speed of light and v the refractive index: we see that the speed is inversely proportional to n, therefore the lower the index of refraction, the higher the speed. So, in this problem, the light will speed up, since it moves into a medium with lower index of refraction.

4 0

3 years ago

Which two factors determine the amount of work done?

nignag [31]

Distance and force.
You need to know how much force was needed and how far it went to calculate how much work was done. The answer is C.

5 0

3 years ago

Read 2 more answers

Based on the type of medium, what can you assume about the speed of sound in glass?

adelina 88 [10]

Answer:

"It will be more than the speed of sound waves in air at 20*C and water at 20*C."

Explanation:

Speed of sound in a medium depends upon the density and elasticity of the medium.

If the elasticity of a medium is greater and the density of that medium is lower, sound will travel faster. Although density is also a factor but the major factor is Elasticity.

Hence, sound travel faster in solids than in liquids and even slower in gases due to elasticity difference.

$Speed of sound = V = \sqrt{\frac{Elasticity}{Density} }$

That is why the speed of sound in glass will be more than the speed of sound waves in air at 20*C and water at 20*C.

5 0

3 years ago

What is the mass number of an atom with five protons and seven neutrons￼

What is the mass number of an atom with five protons and seven neutrons