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mart [117]
4 years ago
15

g Radiation of an unknown wavelength is used in a photoelectric effect experiment on a sodium surface. The maximum kinetic energ

y of the observed electrons is 0.7 eV. What is the wavelength of the light
Physics
1 answer:
Andreas93 [3]4 years ago
4 0

Answer:

λ = 4.1638 10⁻⁷ m

Explanation:

The photoelectric effect was explained by Einstein assuming that the radiation acts like particles and the equation that describes the process is

           K = h f -Ф

where K is the kinetic energy of the emitted electrons, hf  the energy of the photons according to Planck's equation and Ф the work function of the material

In this case they give us the kinetic energy of the electrons

         K = 0.7 eV

The sodium work function is tabulated Ф = 2.28 eV

Let's find the frequency of the photons

            f = (K + Ф) / h

Planck's constant is

          h = 6.626 10⁻³⁴ J s (1 eV / 1.6 10⁻¹⁹ J) = 4.136 10⁻¹⁵ eV s

            f = (0.7 + 2.28) / 4.136 10⁻¹⁵

            f = 7.2050 10¹⁴ Hz

let's find the wavelength using the relationship between speed and frequency and wavelength

            c = λ f

            λ = c / f

            λ = 3 10⁸ / 7.205 10¹⁴

            λ = 4.1638 10⁻⁷ m

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A 5.0 kg block is pushed 2.0 m at a con-
Alona [7]

Answer:

W_F=127.64283 J

Explanation:

Information Given:

m = 5kg  v=constant

Key: μ = Kinetic Friction (Kf)   θ = Theta α = 180° N = Normal Force

W_F=F_ydcosθ

W_F=Fdsinθ

_{net}F_y = sinθ-μN-mg=0

_{net}F_x = 0

N=Fcosθ

Fsinθ-μN=mg

Fsinθ-μFcosθ=mg

F=\frac{mgdsin(theta)}{sin(theta)-(Kf)cos(theta)} →W_F=\frac{mgdsin(theta)}{sin(theta)-(Kf)cos(theta)}

W_F=\frac{(2)(9.81)(2)sin(30)}{sin(30)-(0.40)cos(30)}

W_F=127.64283 J

3 0
3 years ago
Which organs are involved in the process of delivering the digestive juices for the intestines?
timurjin [86]

Answer:

The Liver, Pancreas and Gall Bladder are involved in the process of delivering the digestive juices for the Intestines

Explanation:

4 0
3 years ago
Select the correct answer.
IgorC [24]

Answer:

D. Newton's Third Law of Motion

Explanation:

Newton's law of gravity is definitely not applicable to your hands. So we can cross this bad boy out

Newton's First Law is F=MA (force equals mass times acceleration). This is basically the root of most physics but it isn't the reason for your hand being red after hitting a wall.

Newton's Second law deals with velocities and forces, so even though you are apply a force your are not changing the velocity of the wall much.

Newton's Third Law basically says that for whatever force you apply to an object, that object will apply an equal and opposite force back to you. This is why your hand gets red. When you slap the wall with all your strength, the wall hits your hand back with the same amount of force. The 2nd law can also be seen when you're trying to push a desk and it won't budge. You are pushing on it, but the desk is pushing back. (there are multiple other factors applicable like friction but we physicists like to ignore them :) )

I hope this helps!

7 0
3 years ago
Direct current is the flow of an electric charge _____.
antoniya [11.8K]
For the answer to the question above, i<span>n </span>direct current<span> (</span>DC<span>), the </span>electric charge<span> (</span>current)only flows<span> in one direction. </span>Electric charge<span> in alternating </span>current<span> (AC), on the other hand, changes direction periodically. The voltage in AC circuits also periodically reverses because the </span>current<span> changes direction. So my answer is A.</span>
4 0
3 years ago
Read 2 more answers
A 1,383 kg purple car is driving southbound on a road and collides with a 1,827 kg orange car, that was traveling 31.87 m/s east
user100 [1]

Answer:

Explanation:

We shall apply work energy theorem to calculate the initial velocity just after the collision .

Their kinetic energy will be equal to work done by friction .

force of friction = μ mg , where μ is coefficient of friction , m is total mass and g is acceleration due to gravity

force = .463 x 3210 x 9.8

= 14565.05 N

work done = force x displacement

= 14565.05 x 14.54 = 211775.88 J

now applying work energy theorem

1/2 m v² = 211775.88 , m is composite mass , v is velocity just after the collision

.5 x 3210 x v² = 211775.88

v² = 131.94

v  11.48 m /s

3 0
3 years ago
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