1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kykrilka [37]
3 years ago
9

When light of wavelength 240 nm falls on a potassium surface, electrons having a maximum kinetic energy of 2.93 eV are emitted.

Find values for the following.When light of wavelength 240 nm falls on a potassium surface, electrons having a maximum kinetic energy of 2.93 eV are emitted. Find values for the following. (a) the work function of potassium
eV

(b) the cutoff wavelength
nm

(c) the frequency corresponding to the cutoff wavelength
Hz
Physics
1 answer:
olchik [2.2K]3 years ago
7 0

A) We want to find the work function of the potassium. Apply this equation:

E = 1243/λ - Φ

E = energy of photoelectron, λ = incoming light wavelength, Φ = potassium work function

Given values:

E = 2.93eV, λ = 240nm

Plug in and solve for Φ:

2.93 = 1243/240 - Φ

Φ = 2.25eV

B) We want to find the threshold wavelength, i.e. find the wavelength such that the energy E of the photoelectrons is 0eV. Plug in E = 0eV and Φ = 2.25eV and solve for the threshold wavelength λ:

E = 1243/λ - Φ

0 = 1243/λ - Φ

0 = 1243/λ - 2.25

λ = 552nm

C) We want to find the frequency associated with the threshold wavelength. Apply this equation:

c = fλ

c = speed of light in a vacuum, f = frequency, λ = wavelength

Given values:

c = 3×10⁸m/s, λ = 5.52×10⁻⁷m

Plug in and solve for f:

3×10⁸ = f(5.52×10⁻⁷)

f = 5.43×10¹⁴Hz

You might be interested in
Hull (1943) had rats push a lever that required 21 grams of force to budge. After they had learned to push the lever in order to
Zina [86]

Years of research have demonstrated that rats are intelligent creatures who experience pain and pleasure, care about one another, are able to read the emotions of others, and would assist other rats, even at their own expense.

<h3>Experiments:</h3>

In trials carried out at Brown University in the 1950s, rats were trained to press a lever for food, but they stopped pressing the lever when they noticed that with each press, a rat in an adjacent cage would scream in pain (after experiencing an electric shock).

Rats were trained to press a lever to lower a block that was hanging from a hoist by electric shocks administered by experimenters. A rat was subsequently hoisted into a harness by the experimenters, and according to their notes, "This animal normally shrieked and wriggled sufficiently while dangling, and if it did not, it was jabbed with a sharp pencil until it exhibited indications of discomfort." Even if it wasn't in danger of receiving a shock, a rat watching the scenario from the floor would pull a lever to lower the hapless rodent to safety.

Learn more about experiments on rats here:

brainly.com/question/13625715

#SPJ4

6 0
1 year ago
A woman does 260 J of work to move a table 1.9 m across the floor. What is the magnitude of the force applied by the woman to th
balandron [24]

Answer:136.8N

Explanation:

Work=260joules

Distance=1.9m force=?

Force=work/distance

Force=260/1.9

Force=136.8N

4 0
3 years ago
Two forces, F⃗ 1F→1F_1_vec and F⃗ 2F→2F_2_vec, act at a point. F⃗ 1F→1F_1_vec has a magnitude of 9.20 NN and is directed at an a
marishachu [46]

Answer:

-9.46 N

Explanation:

In order to get the value of the x component of the resultant force, we need to get the value of the x component of each force.

This value will be the projection of the force vector, on the x-axis.

For F₁, as it is directed at an angle of 55.0º above the negative x axis, we can find F₁ₓ just applying the definition of cosine of an angle, as follows:

cos θ = \frac{x}{r}

In this case, x = F₁ₓ, and r = F₁

θ, measured from the positive x axis counterclockwise, is as follows:

θ= 180º-55º = 125º

⇒ F₁ₓ = F₁* cosθ = 9.2 N * cos 125º = -5.28 N

We can repeat the process for F₂, as follows:

For F₂, as it is directed at an angle of 53.3º below the negative x axis, we can find F₂ₓ just applying the definition of cosine of an angle, as follows:

cos θ = \frac{x}{r}

In this case, x = F₂ₓ, and r = F₂

θ, measured from the positive x axis counterclockwise, is as follows:

θ= 180º + 53.3º = 233.3º

⇒ F₂ₓ = F₂* cosθ = 7.00 N * cos 233.3º = -4.18 N

The total component of both forces along the x axis, can be found just adding both components, as follows:

Fₓ = F₁ₓ + F₂ₓ = -5.28 N + -4.18 N = -9.46 N

5 0
3 years ago
Explain resolution of Force​
Margarita [4]

Answer:

it is defined as splitting up the given force into a number of components, without changing its effects on the body is called resolution of forces. A force is generally resolved along with two mutually perpendicular directions.

Explanation:

7 0
3 years ago
How fast did Newton decide a cannon ball shot out in order to escape Earth’s gravity?
arsen [322]

Plugging in for the Earth's mass and for G, we have 11.2 km/s for the escape velocity for an object launched from the Earth's surface. This is about 25,000 miles per hour

7 0
3 years ago
Other questions:
  • A car is 200 m from a stop sign and traveling toward the sign at 40.0 m/s. At this time, the driver suddenly realizes that she m
    10·1 answer
  • ________________________ energy is the energy that an object gets from its position and motion. Question 2 options: mechanical n
    13·1 answer
  • Water waves, earthquake waves, sound waves, and the waves that travel down a rope or spring are all examples of what waves.
    12·1 answer
  • A particle with charge 8 µC is located on the x-axis at the point −10 cm , and a second particle with charge 3 µC is placed on t
    12·1 answer
  • The pedals on a bicycle give a mechanical advantage by allowing you to turn the pedals a __________ distance to turn the _______
    7·2 answers
  • How strongly the planet you're on pulls on you is your
    7·2 answers
  • A 4kg table pushed to the right with an applied force of 50N. The table has a net acceleration of 10 m/s^2 to the right. What is
    13·1 answer
  • How far will a body move in 4 seconds if uniformly accelerated from rest at rate of 2m\sm\s​
    14·1 answer
  • The newest generation of smart phone uses three different batteries connected in a series simultaneously to extend battery life
    14·1 answer
  • What could we call the<br> grocery store?<br> A. Linear motion<br> B. Reference point<br> C. Rotary
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!