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3 years ago

Draw the model of an atom with an atomic number of 7 and a mass number of 15. How many valence electrons are in this atom.

Physics

1 answer:

o-na [289]3 years ago

7 0

Answer:

There are 5 valence electrons

Explanation:

Valence electrons are electrons found in the outermost shell of an atom.

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Two cylinders with the same mass density rC = 713 kg / m3 are floating in a container of water (with mass density rW = 1025 kg /

cluponka [151]

Answer:

$\dfrac{h_2}{h_1}=\dfrac{1}{2}$

Explanation:

Lets take h is height of cylinder immersed in the water

We know that for floating body

$h=\dfrac{\rho_cL}{\rho_l}$

Where $\rho_c$ density of cylinder

$\rho_l$ density of water

For both cylinder fluid is same also density of cylinders are also same

$\dfrac{h_1}{L_1}=\dfrac{h_2}{L_2}$

$\dfrac{h_1}{h_2}=\dfrac{L_1}{L_2}$

$\dfrac{h_1}{h_2}=\dfrac{20}{10}$

$\dfrac{h_2}{h_1}=\dfrac{1}{2}$

3 0

3 years ago

If you are driving 120 km/h along a straight road and you look to the side for 2.0 s , how far do you travel during this inatten

Delicious77 [7]

120 km / 60 min

2 km / 1 min

1 km / 30 sec

0.5 km / 15 sec

0.03333 km / sec

0.03333 km = 33.33 m

8 0

3 years ago

A very thin oil film (n = 1.25) floats on water (n = 1.33). What is the thinnest film that produces a strong reflection for gree

mixer [17]

Answer:

200 nm is the thinnest film that produces a strong reflection for green light with a wavelength of 500 nm

Explanation:

If two reflected waves interfere constructively ,strong reflection is produced. Two reflected waves will experience a phase change

For constructive interference

$2\times n\times t=m\lambda$

for thinnest film m=1

refractive index should be taken for film n=1.25

thickness of the thinnest film is

$t=\frac{m\lambda}{2n} \\t=\frac{1\times 500}{2\times 1.25} \\t=200 nm$

6 0

3 years ago

Orange light of wavelength 0.61 µ m in air enters a block of glass with εr = 1.44. What color would it appear to a sensor embedd

77julia77 [94]

Answer:

$0.5083\ \mu m$

Explanation:

$\lambda_0$ = Actual wavelength = $0.61\ \mu m$

$\varepsilon_r$ = Relative permittivity = 1.44

The observed wavelength in the glass is given by

$\lambda=\dfrac{\lambda_0}{\sqrt{\varepsilon_r}}\\\Rightarrow \lambda=\dfrac{0.61}{\sqrt{1.44}}\\\Rightarrow \lambda=0.5083\ \mu m$

The wavelength lies in the range of green light.

Hence, the observed color of light is $0.5083\ \mu m$

8 0

3 years ago

onsidering light at the two ends of the visible light spectrum, violet light has a _____ wavelength and a _____ photon energy th

Alenkasestr [34]

Answer:

Shorter, higher

Explanation:

6 0

2 years ago