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3 years ago

How many molecules are indicated by writing 2 H2O? A.) 2 B.) 3 C.) 4 D.) 1

Physics

2 answers:

Thepotemich [5.8K]3 years ago

7 0

A, 2 molcules
H2O is one molecule, it has 3 atoms (two hydrogen and one oxygen)
2 H2O are two water molecules

Svet_ta [14]3 years ago

4 0

There are three total molecules in H2O, but the two represents the number of Hyrdogen molecules. So the 2 represents 2 molecules

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Suppose that a public address system emits sound uniformly in all directions and that there are no reflections . The intensity a

Marina86 [1]

Answer:

$I_{2}=2.39*10^{-5} W/m^{2}$

Explanation:

The definition of the intensity in terms of power is given by:

$I=\frac{P}{A}$

Where:

P is the power
A is the area

If the sound emits uniformly in all directions and that there are no reflections, we can assume the geometry of the wave sound is spherical.

Let's recall the area of a sphere is $A = 4\pi R^{2}$

To the first location we have:

$I_{1}=3*10^{-4} W/m^{2}=\frac{P}{4\pi 22^{2}}$

and to the second location we have:

$I_{2}=\frac{P}{4\pi 78^{2}}$

Now, we can divide each intensity to find the second intensity.

$\frac{I_{2}}{I_{1}}=\frac{\frac{P}{4\pi 78^{2}}}{\frac{P}{4\pi 22^{2}}}$

$I_{2}=I_{1}* \frac{22^{2}}{78^{2}}$

$I_{2}=3*10^{-4}\frac{22^{2}}{78^{2}}$

$I_{2}=2.39*10^{-5} W/m^{2}$

I hope it helps you!

5 0

3 years ago

Read 2 more answers

An 80-kgkg quarterback jumps straight up in the air right before throwing a 0.43-kgkg football horizontally at 15 m/sm/s . How f

vladimir1956 [14]

Answer:

V = 0.0806 m/s

Explanation:

given data

mass quarterback = 80 kg

mass football = 0.43 kg

velocity = 15 m/s

solution

we consider here momentum conservation is in horizontal direction.

so that here no initial momentum of the quarterback

so that final momentum of the system will be 0

so we can say

M(quarterback) × V = m(football) × v (football) ........................1

put here value we get

80 × V = 0.43 × 15

V = 0.0806 m/s

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3 years ago

Which statement is true about the atom?

slavikrds [6]

Answer:

Its d

atome contain

negative electrons,

positive protons and uncharged neutrons.

Explanation:

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3 years ago

20. The speed of Light is 3.0 x 108 m/s. Blue Light has a frequency of 6.11 x 1014 Hz. What is its wavelength?

Sladkaya [172]

Answer:

4.91 x 10⁻⁷ m

Explanation:

the applicable formula is

v = fλ

where

v = velocity (i.e speed) = given as 3.0 x 10⁸ m/s

f = frequency = given asw 6.11 x 10¹⁴

λ = wavelength

if we rearrange the equation and substitute the values given above,

v = fλ

λ = v/f

= 3.0 x 10⁸ / 6.11 x 10¹⁴

= 4.91 x 10⁻⁷ m

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iris [78.8K]

Answer: They have different rigidities.

Explanation:

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2 years ago