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3 years ago

TAKING TEST NOW NEED ASAP !!

Physics

2 answers:

Margaret [11]3 years ago

7 0

Answer:

Explanation:

i dont know

just felt

s344n2d4d5 [400]3 years ago

4 0

Answer:

Explanation:

I think that's it. dont know if that's rogue

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What is the best example of physical contamination?

jonny [76]

I might be wrong but I’d say the first one

Answer:
•when a food service worker touches food

Explanation:
The worker is physically putting his hands on the food, therefore contaminating it which whatever’s on his hands

-YW!! <33

6 0

3 years ago

Light with a wavelength range of 141–295 nm shines on a silicon surface in a photoelectric effect apparatus, and a reversing pot

Ksju [112]

Answer:

a) the longest wavelength of the light that will eject electrons from the silicon surface is 258.7891 nm

b) maximum kinetic energy will electrons reach the anode is 0.5098 eV

Explanation:

Given:

Wavelength range = 141-295 nm

Potential of 3.5 V

For the silicon, the work function is Φ = 4.8 eV = 7.68x10⁻¹⁹J

Questions:

a) What is the longest wavelength of the light that will eject electrons from the silicon surface, λ = ?

b) With what maximum kinetic energy will electrons reach the anode,

a) The longest wavelength that will eject electrons:

$\lambda =\frac{hc}{\phi }$

Here

h = Planck's constant = 6.625x10⁻³⁴J s

c = speed of light = 3x10⁸m/s

Substituting values:

$\lambda =\frac{6.625x10^{-34}*3x10^{8} }{7.68x10^{-19} } =2.588x10^{-7} m=258.7891nm$

b) The maximum kinetic energy (one electron):

$K=\frac{hc}{\lambda } -\phi =\frac{6.625x10^{-34}*3x10^{8} }{141x10^{-9} } -7.68x10^{-19} =6.416x10^{-19} J=4.0098eV$

Now, you need to calculate the potential difference:

$K'=eV$

Here

e = charge of electron = 1.6x10⁻¹⁹C

Substituting:

$K'=1.6x10^{-19} *3.5=5.6x10^{-19} J=3.5eV$

Now, the maximum kinetic energy of the electrons:

Kmax = 4.0098 - 3.5 = 0.5098 eV

6 0

4 years ago

Why are logarithmic scales useful in earth science?

Yuri [45]

The differences in energy released by earthquakes are too large to express with linear scales.

4 0

3 years ago

Salmon often jump waterfalls to reach their

____ [38]

Answer:

Using the range formula R = v^2 sin 2 theta / g

or v^2 = R * g / sin 86.4

v^2 = 3.14 m * 9.81 m/s2 / .998

v^2 = 30.9 m^2 / s^2

v = 5.56 m/s

This hasn't really proved the question - this would give

vy = 5.56 * sin 43.2 = 3.81 m/s

vx = 5.56 * cos 43.2. = 4.05 m/s

t = 1.57 / 4.05 = .387 sec to reach the waterfall

h = 3.81 * .387 - 4.9 (.387)^2 = .74 m well above the height of the falls

There seems another way to do this

vy / vx = tan 43.2 vy = .939 vx

h = vy t - 1/2 g t^2 and t = 1.57 / vx

h = 1.57 tan 43.2 - 4.9 (1.57 / vx)^2

Solving for vx I get vx = 3.26 m/s vy = 3.06 m/s v = 4.47 m/s

5 0

3 years ago

Hey guys, is this question for a series circuit or for parallel?

Mandarinka [93]

Answer:

I need help with the same question

Explanation:

3 0

3 years ago