Lithium was one of the metals studied by the American physicist Robert Millikan in his research on the photoelectric effect. When illuminated with blue light of frequency 6.64 x 10" Hz, the photoelectrons ejected from a lithium surface have a maximum kinetic energy of 0.332 eV. What is the threshold frequency for lithium? For this problem, let the value of Planck's constant, h, be 6.63 x 10J's

Answers

Answer 1

Answer:

 f = 7.9487 10¹³ Hz

Explanation:

The photoelectric effect was correctly explained by Einstein assuming that the radiation is composed of photons, which behave like particles.

           hf = K + Ф

It indicates the frequency and the kinetic energy, let's look for the work function

          Ф = hf - K

let's reduce the magnitudes to the SI system

          K = 0.332 eV (1.6 10⁻¹⁹ J / 1 eV) = 0.5312 10⁻⁻¹⁹ J

let's calculate

          Ф = 6.63 10⁻⁻³⁴  6.64 10¹¹ - 0.5312 10⁻¹⁹

          Ф = 4.40 10⁻²² - 0.5312 10⁻¹⁹

          Ф = 5.27 10⁻²⁰ J

for the minimum frequency that produces photoelectrons, the kinetic energy is zero

           hf = Ф  

           f = Ф / h

           f = 5.27 10⁻²⁰ / 6.63 10⁻³⁴

           f = 7.9487 10¹³ Hz


Related Questions

1. Swordfish are capable of stunning output power for short bursts. A 650 kg swordfish has a cross-sectional area of 0.92 m2 and a drag coefficient of 0.0091- very low due to some evolutionary adaptations. Such a fish can sustain a speed of 30 m/s for a few seconds. Assume seawater has a density of 1026 kg/m3. a) How much power does the fish need to put out for motion at this high speed

Answers

Answer:

[tex]P_{sp}=178.4W/kg[/tex]

Explanation:

From the question we are told that:

Mass of fish [tex]m_f=650kg[/tex]

Cross-sectional area [tex]A=0.92 m^2[/tex]

Drag coefficient of [tex]\mu= 0.0091[/tex]

Seawater  density [tex]\rho= 1026 kg/m^3.[/tex]

Speed of  Fish [tex]v=30 m/s[/tex]  

Generally the equation for Drag force F_d is mathematically given by

[tex]F_d = \mu * \rho *A v^2 /2[/tex]

[tex]F_d = 0.0091* 0.92* 1026* 30^2/2 \\F_d= 3865. 35 N[/tex]  

Generally the equation for high speed  Power  [tex]P_{sp}[/tex] is mathematically given by

[tex]P_{sp}=3865*35*\frac{v}{m_f}[/tex]

[tex]P_{sp}=F_d*35*\frac{30}{650}[/tex]

[tex]P_{sp}=178.4W/kg[/tex]

The image below represents water's... *

Answers

Answer:

it represents the physical changes.

Explanation:

I




Sal is experimenting with materials that dissolve in water. He finds a material that dissolves well in water. Which of these could it
be?

Answers

any pics? so i can see the question ⁉️

PLEASE HELP

name 4 fundamentally different options for cooking a chicken​

Answers

Answer:

roasting,

broiling,

pan-broiling,

pan-frying,

grilling.

Explanation:

good luck

Answer:

Explanation:

1. Stir frying

2. Pan frying

3. Grilling /BBQ

4. Baking/roasting

List the two factors that create orbital motion and describe how each factor affects the motion.​

Answers

Sir Isaac Newton concluded that two factors—inertia and gravity–combine to keep Earth in orbit around the sun, and the moon in orbit around Earth. Hope this helps!

Select the correct answer.
Which type of energy is thermal energy a form of

Answers

kinetic energy. thermal energy (a low form of energy ) is a form of kinetic energy as it is produced as a result of motion of particles either if they vibrate at their position or they move along longer paths. Motion produces friction or resistance which leads to excitation and thus the heat is produced. The higher the motion of the particles, the higher would be the thermal energy.

Why does an energy transfer not always result in phase change?

Answers

Answer:

Explanation:

The energy transfer are not changing in kinetic energy. They are changes in bonding energy between the molecules.

An 85-year-old woman who was having trouble breathing checked into the hospital. There, her heart stopped beating and doctors determined she suffered heart failure. After being resuscitated, she was in a coma and had no brain function. Her family then made the difficult decision to take her off life support, and the woman passed away.

Which order of events did the woman experience?
brain death Right arrow. clinical death Right arrow. somatic death
somatic death Right arrow. brain death Right arrow. clinical death
clinical death Right arrow. brain death Right arrow. somatic death
clinical death Right arrow. somatic death Right arrow. brain death

Answers

Answer:c

Explanation:

clinical death Right arrow. brain death Right arrow. somatic death this order of events did the woman experience. Hence option C is correct.

What is death ?

The permanent end of all biological activities that support an organism is defined as death. Death may also be defined as the permanent cessation of functioning of the entire brain, including the brainstem, in creatures with a brain, and brain death is frequently used as a legal definition of death.Normally, the remnants of a previous creature begin to degrade quickly after death. Death is an unavoidable process that happens in all species. Turritopsis dohrnii, for example, is physiologically immortal. They can, however, perish from causes other than ageing.

It has been difficult to determine when someone has died. Initially, death was defined as the cessation of breathing and heartbeat.

To know more about Death :

https://brainly.com/question/31108171

#SPJ3.

Determine the kinetic energy of a 2000 kg roller coaster car that is moving at the speed of 10 ms

Answers

Answer:

[tex]\boxed {\boxed {\sf 100,000 \ Joules}}[/tex]

Explanation:

Kinetic energy is energy due to motion. The formula is half the product of mass and velocity squared.

[tex]E_k= \frac{1}{2} mv^2[/tex]

The mass of the roller coaster car is 2000 kilograms and the car is moving 10 meters per second.

m= 2000 kg s= 10 m/s

Substitute these values into the formula.

[tex]E_k= \frac{1}{2} (2000 \ kg ) \times (10 \ m/s)^2[/tex]

Solve the exponent.

(10 m/s)²= 10 m/s * 10 m/s= 100 m²/s²

[tex]E_k= \frac{1}{2} (2000 \ kg ) \times (100 \ m^2/s^2)[/tex]

Multiply the first two numbers together.

[tex]E_k= 1000 \ kg \times (100 \ m^2/s^2)[/tex]

Multiply again.

[tex]E_k= 100,000 \ kg*m^2/s^2[/tex]

1 kilogram square meter per square second is equal to 1 Joule. Our answer of 100,000 kg*m²/s² is equal to 100,000 Joules.

[tex]E_k= 100,000 \ J[/tex]

The roller coaster car has 100,000 Joules of kinetic energy.

Which is not a component of an electromagnet?
A. solenoid
B. power source
C. ferromagnetic core
D. permanent magnet

Answers

It would probably be B

a car is traveling with a velocity of 40 m/s and has a mass of 1120kg the car has kinetic energy

Answers

As shown in picture please give me Brainly list

describe the human condition before Science and technology was practice.​

Answers

Their condition was very very bad .doing everything by themselves

what is the relationship between the perimeter and the side length of anequilateral triangle ?

Answers

Answer:

The length of the equilateral triangle's side is the length of the hypotenuse of the 30-60-90. Using this ratio, we find that the length of this triangle's hypotenuse is 4. Thus the perimeter of the equilateral triangle will be 4 multiplied by 3, which is 12.

Does time stand still in space

Answers

Answer:

[tex]\underline{\textsf{\textbf{Answer -}}}[/tex]

No & Yes - the case depends actually.

You can't make the velocity zero and expect to stay in space. you will need to constantly fire the engine to hold youself in position (this is possible, until you run out of fuel).

Yes, it is possible to fire the engine and lift off earth into space, and then fire in the opposite direction to earths movement until you are still, relative to the sun. But if you now turn the engine off, the suns gravity will pull you down and directly into the sun.

its the earths forward motion that prevents it falling into the sun

Answer:

No & Yes - the case depends actually.

You can't make the velocity zero and expect to stay in space. you will need to constantly fire the engine to hold youself in position (this is possible, until you run out of fuel).

Yes, it is possible to fire the engine and lift off earth into space, and then fire in the opposite direction to earths movement until you are still, relative to the sun. But if you now turn the engine off, the suns gravity will pull you down and directly into the sun.

its the earths forward motion that prevents it falling into the sun

Which list of elements is placed in order from most reactive to least reactive?
A. K, Ca, Kr, Ge
B. K, Ca, Ge, Kr
C. Ca, K, Kr, Ge
D. Ge, Kr, Ca, K

Answers

All four elements given in the answer choices are on the same period. The least reactive element should be Kr, since it is a noble gas. By that fact alone, B would be the correct answer.

B is also correct as non-d-block metals increase in reactivity from left to right on along a period. The order of the metals (Ge is often considered a metalloid) conforms with that trend.

A car travelling at 25 m/s has momentum 20,000 Kgm/s, calculate the mass of the car.

Answers

[tex] \Large {\underline { \sf {Required \; Solution :}}}[/tex]

We have

Velocity of the car, v = 25 m/sMomentum of the car, P = 20,000 kg.m/s

We have been asked to calculate the mass of the car, m.

[tex]\qquad\implies\boxed{\red{\sf{ P = mv}}}\\[/tex]

P denotes momentumm denotes massv denotes velocity

[tex] \quad \twoheadrightarrow\sf { 20000 = 25m} \\ [/tex]

[tex] \quad \twoheadrightarrow\sf { \cancel{\dfrac{20000}{25}} = m} \\ [/tex]

[tex]\quad\twoheadrightarrow\boxed{\red{\sf{ m = 800 \; kg}}}\\[/tex]

Therefore, mass of the car is 800 kg.

SEND HELP
Which of these is one of the five determinants of health?
A. The gender of your doctor
B. Your access to health services
C. The type of sport you play
D. The amount
your insurance deductible

Answers

Answer:

B

Explanation:


Find the Net Force on a truck with a mass of 1,500kg and an acceleration
of 10m/s2?

Answers

Answer:

15,000 N

Explanation:

F = ma = (1,500 kg)(10 m/s^2) = 15,000 N

How does the observed spectrum above compare to the thermal radiation curves
you saw in the last section? What are the similarities and differences?

Answers

There is no observed spectrum above, and I didn't see any curves in the last section.  So I guess they're similar in that respect.

Otherwise, your question is quite intriguing.

Fizik
Dua perintang 5 Ω dan 10 Ω disambung selari dengan 9 V bekalan kuasa. Kira kuasa output bekalan kuasa.​

Answers

Answer:

P = 24.32 W

Explanation:

The question is, "Two resistors 5 Ω and 10 Ω are connected in parallel with a 9 V power supply. Calculate the output power of the power supply.".

The voltage of the power supply, V = 9 V

Resistor 1, R₁ = 5 Ω

R₂ = 10 Ω

The equivalent of parallel combination of resistors is given by :

[tex]\dfrac{1}{R_{eq}}=\dfrac{1}{R_1}+\dfrac{1}{R_2}\\\\\dfrac{1}{R_{eq}}=\dfrac{1}{5}+\dfrac{1}{10}\\\\R_{eq}=3.33\ \Omega[/tex]

The power of the output is given by :

[tex]P=\dfrac{V^2}{R_{eq}}\\\\=\dfrac{9^2}{3.33}\\\\P=24.32\ W[/tex]

So, the output power is equal to 24.32 W.

Select the correct answer.
Which of the following best describes an intermediate runner?

A. Able to alternate running 2 minutes, walking 1 minute

B. Able to run a mile without stopping

C. Able to run at least 30 minutes, 3-5 times a week

D. Able to run 1 mile in 10 minutes or less

Answers

I would say answer D

A is very easy, so that's off the table, while be is a little too advanced for intermediate, and C is way to advanced for intermediate.

So yeah, D

It would probably be D

What process changes a liquid to a solid?
A. Evaporation
B. Melting
C. Adding heat
D. Freezing

Thank you!!!<3

Answers

Answer:

D. Freezing?

Explanation:

Get water, put it in the freezer, turns into ice after a few hours.

A bicycle pump contains 200 cm3 of air and is connected to a bicycle tyre. The volume of the tyre is 800 cm3. The pressure of the air in the tyre (it is ‘flat’) is 1.0 atmosphere, the same as the air in the pump. (= volume1). What is the total volume of the air initially?

Answers

Answer:

The total initial volume of air in the tire is 800 cm³

Explanation:

Given;

volume of air in the bicycle pump, V₁ = 200 cm³

volume of the tire, V₂ = 800 cm³

The total initial volume of air in the tire is 800 cm³ and when the pump is pushed in, the total volume of air in the tire becomes 200 cm³. This occurs because the new air pumped into the tire through the bicycle pump compresses the air that was previously in the tire and raises the pressure of the tire that was initially flat.

From Boyle's law, a decrease in volume causes an increase in pressure.

1. Fill in the blanks. (3 pts)
a.
is the amount of matter in an object.
b.
is the unit of measurement for force.
c.
p = m* v is

Answers

Answer:

a) mass

b) Newtons

c) momentum formula where p stands for momentum, m stands for mass, and v stands for velocity

Hope this helps!

Answer:

a mass

b acceleration

mass is the matter in an object

force is a pull or push of an object or body

4. How does the changing volume of the air inside the balloon affect the density


Answers

Answer:

please give me brainlist and follow

Explanation:

Since density is described as mass divided by volume, as volume decreases, density increases. With enough drop in volume, the helium balloon becomes too dense to float.

How do scientists use light years?to report report distances distances between between objects objects in in space space and and study study the the early early universeuniverseto to measure measure how how fast fast an an object object is is traveling traveling and and determine determine the the origins origins of of the the universeuniverseto to measure measure the the amount amount of of light light that that a a star star produces produces and and determine determine how how hot hot it it is is burningburningto to determine determine the the age age of of an an object object in in space space and and study study how how it it was was formedformed

Answers

Answer:to measure distances between objects and to study the early universe

Explanation:

I had this question and I got it right

A baby was born on his due date, but doctors determined that a valve in his heart was too short to adequately pump blood to his body. The baby passed away after eight months. Which best describes the cause of his death?
He had a congenital condition.
He was premature.
He died in an accident.
He suffered SIDS.

Answers

Answer:

He had a cogenital condition

Explanation:

cogenital conditions are present before or at the time of birth and are considered birth defects

Answer:

The answer is C- He had a congential condition.

Explanation:

Edge

A marble is placed at the bottom of a semi-spherical bowl, as shown in the figure. The marble is then displaced from the bottom of the bowl to a position about halfway from the top of the bowl. The marble is then released from rest such that the marble always remains in contact with the bowl. Students observe that the marble rolls back and forth as it oscillates about the bottom of the bowl. Which of the following statements best explains why the marble undergoes oscillatory motion?
a)The sides of the bowl become steeper at positions farther from the bottom of the bowl.b) The net force exerted on the marble always has a component directed toward the bottom of the bowl. c) The normal force exerted on the marble decreases with increasing distance from the bottom of the bowl. D ) The gravitational force exerted on the marble is constant in magnitude and direction.​

Answers

Answer:

It is D

Explanation:

The explanation why the marble undergoes oscillatory motion should be option D.

What is oscillatory motion?

An object should be classified as the motion oscillates related to an equilibrium position because of the restoring force or torque.  This motion should be significant to study various phenomena like electromagnetic waves, molecules. etc. In the case when the gravitational force should be exerted on the marble here the magnitude and the direction should be the same.

learn more about the motion here: https://brainly.com/question/16335988

The red shifting of the nebula that Slipher observed was also referred to as what?

Answers

Answer:

Slipher developed spectrographic methods that allowed researchers to see a Doppler effect in the distances of what were then called “spiral nebula,” what we today call galaxies. Simply put, by measuring the longer wavelength red shift (objects moving away) and shorter wavelength blue shift (objects moving closer), Slipher demonstrated that the universe was not static.

Explanation:

What is the wavelength associated with 0.113kg ball traveling with velocity of 43 m/s?

Answers

Answer:

Wavelength = 1.36 * 10^{-34} meters

Explanation:

Given the following data;

Mass = 0.113 kg

Velocity = 43 m/s

To find the wavelength, we would use the De Broglie's wave equation.

Mathematically, it is given by the formula;

[tex] Wavelength = \frac {h}{mv} [/tex]

Where;

h represents Planck’s constant.

m represents the mass of the particle.

v represents the velocity of the particle.

We know that Planck’s constant = 6.6262 * 10^{-34} Js

Substituting into the formula, we have;

[tex] Wavelength = \frac {6.6262 * 10^{-34}}{0.113*43} [/tex]

[tex] Wavelength = \frac {6.6262 * 10^{-34}}{4.859} [/tex]

Wavelength = 1.36 * 10^{-34} meters

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