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
shutvik [7]
3 years ago
15

Light is shining perpendicularly on the surface of the earth with an intensity of 680 W/m^2. Assuming that all the photons in th

e light have the same wavelength (in vacuum) of 678 nm, determine the number of photons per second per square meter that reach the earth.
Physics
1 answer:
andrew11 [14]3 years ago
4 0

Answer:

3.066×10^21  photons/(s.m^2)

Explanation:

The power per area is:

Power/A = (# of photons /t /A)×(energy / photon)

E/photons = h×c/(λ)

photons /t /A = (Power/A)×λ /(h×c)  

photons /t /A = (P/A)×λ/(hc)

photons /t /A = (680)×(678×10^-9)/(6.63×10^-34)×(3×10^-8)

                      = 3.066×10^21

Therefore, the number of photons per second per square meter 3.066×10^21  photons/(s.m^2).

You might be interested in
B. Projectile on cliff (range)
dimulka [17.4K]

Answer:

x = 41.28 m

Explanation:

This is a projectile launching exercise, let's find the time it takes to get to the base of the cliff.

Let's start by using trigonometry to find the initial velocity

         cos 25 = v₀ₓ / v₀

         sin 25 = Iv_{oy} / v₀

         v₀ₓ = v₀ cos 25

         v_{oy} = v₀ sin 25

         v₀ₓ = 22 cos 25 = 19.94 m / s

         v_{oy} = 22 sin 25 = 0.0192 m / s

let's use movement on the vertical axis

         y = y₀ + v_{oy} t - ½ g t²

     

when reaching the base of the cliff y = 0 and the initial height is y₀ = 21 m

         0 = 21 + 0.0192 t - ½ 9.81 t²

         4.905 t² - 0.0192 t - 21 = 0

         t² - 0.003914 t - 4.2813 =0

we solve the quadratic equation

        t = \frac{ 0.003914\  \pm \sqrt{0.003914^2 + 4 \ 4.2813 }   }{2}

        t = \frac{0.003914 \ \pm 4.13828}{2}

        t₁ = 2.07 s

        t₂ = -2.067 s

since time must be a positive scalar quantity, the correct result is

        t = 2.07 s

now we can look up the distance traveled

         x = v₀ₓ t

         x = 19.94  2.07

         x = 41.28 m

5 0
3 years ago
A gas has an initial volume of 212 cm3 at a temperature of 293 K and a pressure of 0.98 atm. What is the final pressure of the g
Serggg [28]
If the ga has 212 cm3 the. Temperature was at a 2
7 0
3 years ago
Read 2 more answers
The kinetic energy of an object with a mass of 6.8 kg and a velocity of 5.0 m/s is J. (Report the answer to two significant figu
abruzzese [7]

Answer:

\boxed{\sf Kinetic \ energy \ (KE) = 85 \ J}

Given:

Mass (m) = 6.8 kg

Speed (v) = 5.0 m/s

To Find:

Kinetic energy (KE)

Explanation:

Formula:

\boxed{ \bold{\sf KE =  \frac{1}{2} m {v}^{2} }}

Substituting values of m & v in the equation:

\sf \implies KE =  \frac{1}{2}  \times 6.8 \times  {5}^{2}

\sf \implies KE = \frac{1}{ \cancel{2}}  \times  \cancel{2} \times 3.4 \times 25

\sf \implies KE =3.4 \times 25

\sf \implies KE = 85 \: J

8 0
3 years ago
Read 2 more answers
........................................................ waves are detected first because they move so fast .
wel

<u><em>PRIMARY </em></u>Waves Are Detected First Because They Move So Fast.

<u><em>RIGHT</em></u> Angles To The Direction of Movement.

A Kind Of Scale Used To Measure The Amount of Seismic Energy Released By An Earthquake <u><em>RICHTER SCALE</em></u>

7 0
3 years ago
The magnetic field at the equator points north. if you throw a positively charged object (for example, a baseball with some elec
asambeis [7]
Recall the equation for magnetic force:

F = qv x B          *x is cross product, not separate variable!

If the magnetic field points towards N and you throw E, then the magnetic force would point up, or out of the page. Use the right-hand rule. You point your finger towards the direction of the object, and curl your finger to the magnetic field. Your thumb is the direction of the magnetic force.

Hope this helps!
7 0
3 years ago
Other questions:
  • The purple arrow shows speed and direction of the ball. This arrow is called what?
    15·2 answers
  • There are 92 naturally occurring elements. How does this relate to the number of compounds?
    12·1 answer
  • a 25 newton force applied on an object moves it 50 meters. the angle between the force and displacement is 40.0°. what is the va
    14·1 answer
  • Chameleons catch insects with their tongues, which they can rapidly extend to great lengths. In a typical strike, the chameleon'
    9·1 answer
  • Unit of gravitational force ​
    8·1 answer
  • Without steering, a car (mass 1501 kg) can travel with a certain speed around a banked frictionless corner angled at 25.0° to th
    6·1 answer
  • During a thunderstorm, you should crouch under a tree for shelter. <br> a. True<br> b. False
    11·1 answer
  • Which frequency would be the third harmonic in a series for an open-pipe resonator if the fundamental is 440 Hz
    5·1 answer
  • An airplane is flying in a horizontal circle at a speed of 100 m/s. The 80.0 kg pilot does not want the centripetal acceleration
    14·1 answer
  • 2. Using a giant screw, a crew does 650 J of work to drill a hole into a rock.
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!