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3 years ago

Helium is considered a noble gas because it has a _blank___ valence electron shell

2 answers:

5 0

Noble gases are elements found in the last column of the periodic table and are characterized by their reaction rate, or lack there of. Each element in that column does not react since they do not need to gain or lose electrons. So, helium has a "full" valence electron shell.

3241004551 [841]3 years ago

3 0

Helium has completely filled valence orbitals similar to noble gases and is chemically inert at room temperature.

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When you describe a liquid as thick, are you saying that it has a high or a low viscosity?

Umnica [9.8K]

It is commonly perceived as "thickness", or resistance to pouring. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. Thus, water is "thin", having a low viscosity, while vegetable oil is "thick" having a high viscosity.

6 0

2 years ago

A diverging lens has a focal length of -30.0 cm. An object is placed 18.0 cm in front of this lens.

yulyashka [42]

Answer:

A) Calculate the distance

8 0

3 years ago

in a certain pinhole camera, the screen is 10 cm from the pinhole. When the pinhole is placed 6 cm away from a tree ,a sharp ima

vagabundo [1.1K]

Answer:

Height of the tree is 9.6 cm

Explanation:

We know that, Magnification of an image is written as follows.

$\left(\frac{H_{i}}{H_{o}}\right)=\left(\frac{D_{i}}{D_{o}}\right)$

Where,

$\begin{array}{l}{\mathrm{H}_{0}=\text { height of the object }} \\ {\mathrm{H}_{\mathrm{i}}=\text { height of the image }} \\ {\mathrm{D}_{0}=\text { distance of the object }} \\ {\mathrm{D}_{\mathrm{i}}=\text { distance of the image }}\end{array}$

As per given question,

$\begin{array}{l}{\mathrm{H}_{1}=\text { height of the image }=\text { height of the image of the tree on screen }=16 \mathrm{cm}} \\ {\mathrm{D}_{0}=\text { distance of the object }=\text { distance of the tree from the pinhole }=6 \mathrm{cm}} \\ {D_{1}=\text { distance of the image }=\text { distance of the image from the pinhole }=10 \mathrm{cm}} \\ {\mathrm{H}_{0}=\text { height of the object }=\text { height of the tree }}\end{array}$

Substitute the values in the above formula,

$\begin{array}{l}{\left(\frac{H_{i}}{H_{o}}\right)=\left(\frac{D_{i}}{D_{o}}\right)} \\ {\left(\frac{16}{H_{o}}\right)=\left(\frac{10}{6}\right)} \\ {\mathrm{H}_{\mathrm{o}}=\left(\frac{16 \times 6}{10}\right)} \\ {\mathrm{H}_{\mathrm{o}}=9.6 \mathrm{cm}}\end{array}$

Height of the tree is 9.6 cm.

8 0

3 years ago

The deck of a bridge is suspended 235 feet above a river. If a pebble falls off the side of the bridge, the height, in feet, of

Aleks04 [339]

Answer:

(a) 1, average velocity = -65.6 m/s

2, average velocity = -64.8 m/s

3, average velocity = -64.16 m/s

(b) The instantaneous velocity is -96 m/s

Explanation:

(a)

Average velocity is given by;

$y(t_2,t_1) = \frac{y(t_2) - y(t_1)}{t_2-t_1}$

(1)

$y(2.1,2) = \frac{(235-16*2.1^2) - (235-16*2^2)}{2.1-2}\\\\ y(2.1,2) = -65.6 \ m/s$

(2)

$y(2.05,2) = \frac{(235-16*2.05^2) - (235-16*2^2)}{2.05-2}\\\\ y(2.05,2) = -64.8 \ m/s$

(3)

$y(2.01,2) = \frac{(235-16*2.01^2) - (235-16*2^2)}{2.01-2}\\\\ y(2.01,2) = -64.16 \ m/s$

b. y = 235 - 16t²

The instantaneous velocity is given by;

v = dy /dt

dy / dt = -32t

when t = 3 s

v = -32(3)

v = -96 m/s

5 0

3 years ago

If a sound wave is produced by a speaker at room temperature and has a

Oksana_A [137]

Answer: 183.8Hz

Explanation:

Given that,

wavelength of sound (λ) = 1.85 m

frequency of the sound (F) = ?

Recall that the speed of sound (V) in air is a constant with a value of 340m/s

So, apply the formula

V = F λ

340 m/s = F x 1.85 m

F = 340m/s / 1.85m

F = 183.8Hz

Thus, the frequency of the sound that is

generated is 183.8 hertz

3 0

3 years ago