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fenix001 [56]
3 years ago
6

PLEASE HELP. HOW DO U CALCULATE??

Physics
1 answer:
tatyana61 [14]3 years ago
5 0

-- The energy of one photon is <em>(h · frequency of the light)</em>

' h ' is 6.626 × 10⁻³⁴ m²-kg/s  ("Planck's Constant")

-- The question doesn't tell you the frequency of the light from the LED, but it tells you the wavelength, and  

<em>Frequency = (speed of light) / (wavelength) </em>.

-- Now you have everything you need to calculate the <em>energy carried by one photon from the LED</em>.

-- The power of the light from the LED is 120 milliwatts.  That's <em>0.120 Joule of energy per second</em>.

Now you should be able to find the number of photons per second.  It's going to be  <em>(0.120 Joule) / (energy carried by one photon)</em> .


When I scribbled it out on a scrap of scratch paper, I got 3.853 x 10³⁸ photons, but you'd better really check that out.

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With what speed must you approach a source of sound to observe a 25% change in frequency?
insens350 [35]
Sound source is at rest, you are moving with velocity v, f = frequency, c = speed of sound:

f = f0(1 + v/c)

115 = 100(1 + v/343)
115 = 100 + 100v/343
15 = 100v/343
v = 15*343/100
<span> v = 51,45 m/s </span>
5 0
3 years ago
Because weight is a measurement of the amount of gravity pulling on an object, weight is considered a ______. Question 18 option
Andrews [41]

Answer: Force I believe.

6 0
2 years ago
A pendulum oscillates 12 times in 4 seconds. what is the length of the pendulum?
seraphim [82]

Answer:

L = 2.8 cm

Explanation:

Period T = 4 / 12 = 1/3 s

T = 2π√(L/g)

L = (T/2π)²g

L = ((1/3)/2π)²9.8 = 0.02758... ≈ 2.8 cm

6 0
3 years ago
Calculate the acceleration of a bus that goes
Svet_ta [14]

The acceleration of the bus is 1.11 meters per second square to the direction of motion

Explanation:

Acceleration is the rate of change of velocity

The formula of the acceleration is a=\frac{v_{2}-v_{1}}{t} , where

  • v_{1} is the initial velocity
  • v_{2} is the final velocity
  • t is the time

A bus that goes  from 10 km/h to a speed of 50 km/h in 10 seconds

→ v_{1} = 10 km/h

→ v_{2} = 50 km/h

→ t = 10 seconds

Change the unite of the time from seconds to hour

→ 1 hour = 60 × 60 = 3600 seconds

→ 10 seconds = \frac{10}{3600}=\frac{1}{360} hour

Substitute these values in the formula of the acceleration above

→ a=\frac{50-10}{\frac{1}{360}}

→ a = 14400 km/h²

To change the unit of acceleration to meter per second change the

  kilometer to meter and the hour to seconds

→ 1 km = 1000 m

→ 1 hour = 3600 seconds

→ a=\frac{14400*1000}{(3600)^{2}}=\frac{10}{9}

→ a = 1.11 m/sec².

The acceleration of the bus is 1.11 meters per second square to the direction of motion

Learn more:

You can learn more about the acceleration in brainly.com/question/6323625

#LearnwithBrainly

4 0
3 years ago
Consider the speed of light in another universe to be only 100 m/s. Two cars are traveling along a highway in opposite direction
olganol [36]

Answer:

-62.45m/s and +62.45m/s

Explanation:

The formula for relativistic speed

This is the speed of A with respect to B

V_{AB}=\frac{V_{A}-V_{B}}{1-\frac{V_{A}V_{B}}{C^2} }

where

V_{A} will be the velocity of person 1: 39m/s

V_{B} will be the velocity of person 2: -31m/s (negative because is travelling in opposite direction)

and C the velocity of light: 100m/s

The velocity of person 1 measured by person 2 is:

V_{AB}=\frac{39m/s-(-31m/s)}{1-\frac{(39m/s)(-31m/s)}{(100m/s)^2}}=62.45m/s

The velocity of person 2 measured by person 1 is:

V_{BA}=\frac{V_{B}-V_{A}}{1-\frac{V_{B}V_{A}}{C^2} }

V_{BA}=\frac{-31m/s-39m/s}{1-\frac{(-31m/s)(39m/s)}{(100)^2} }=-62.45m/s

8 0
3 years ago
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