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4 years ago

A number n plus 7 is less than or equal to 9.

Physics

1 answer:

gizmo_the_mogwai [7]4 years ago

7 0

Answer:

n=2

Explanation:

n+7=9

n=9-7

n=2

+ -= -

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All stored energy is potential<br>energy. Do you agree?<br>

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Answer:

yes I agree Because........

Explanation:

Potential energy is stored energy. Potential energy is the energy that exists by virtue of the relative positions of the objects within a physical system. This form of energy has the potential to change the state of other objects around it, for example, the configuration or motion.

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3 years ago

As __________ increases, the humidity of that area will __________. temperature; also increase dew; also increase rainfall; alwa

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How much power would be needed to lift a 1.0x10^3N crate 1.5m in 5 seconds?

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3 years ago

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A boy on the edge of a vertical cliff 20-m high throws a stone horizontally outwards with a speed of 20 m/s. It strikes the grou

Komok [63]

Answer:

Horizontal distance from the foot of the cliff is 40 m

Explanation:

Given :

Speed of stone $v = 20\frac{m}{s}$

Vertical distance $d = 20$ m

Gravitational acceleration $g = 10$ $\frac{m}{s^{2} }$

From the kinematics equation,

$d = v_{o} t + \frac{1}{2} at^{2}$

Where $v_{o} =$ initial velocity ( $v_{o} = 0$ )

So time take to fall down,

$t = \sqrt{\frac{2d}{a} }$

$t = \sqrt{4}$

$t = 2$ sec

Now find horizontal distance travel by stone,

$x = vt$

$x = 20 \times 2$

$x = 40$ m

Therefore, the horizontal distance travel by stone is 40 m

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3 years ago

The n = 2 to n = 6 transition in the bohr hydrogen atom corresponds to the ________ of a photon with a wavelength of ________ nm

Colt1911 [192]

The energy levels of the hydrogen atom are quantized and their energy is given by the approximated formula
$E=- \frac{13.6}{n^2} [eV]$
where n is the number of the level.

In the transition from n=2 to n=6, the variation of energy is
$\Delta E=E(n=6)-E(n=2)=-13.6 ( \frac{1}{6^2}- \frac{1}{2^2} )[eV]=3.02 eV$
Since this variation is positive, it means that the system has gained energy, so it must have absorbed a photon.

The energy of photon absorbed is equal to this $\Delta E$ . Converting it into Joule,
$\Delta E=3.02 eV=4.84 \cdot 10^{-19}J$
The energy of the photon is
$E=hf$
where h is the Planck constant while f is its frequency. Writing $\Delta E=hf$ , we can write the frequency f of the photon:
$f= \frac{\Delta E}{h}= \frac{4.84 \cdot 10^{-19}J}{6.63 \cdot 10^{-34}m^2 kg/s}=7.29 \cdot 10^{14}Hz$

The photon travels at the speed of light, $c=3 \cdot 10^8 m/s$ , so its wavelength is
$\lambda = \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{7.29 \cdot 10^{14}Hz}=4.11 \cdot 10^{-7}m=411 nm$

So, the initial sentence can be completed as:
The n = 2 to n = 6 transition in the bohr hydrogen atom corresponds to the "absorption" of a photon with a wavelength of "411" nm.

4 0

4 years ago

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