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Degger [83]
3 years ago
8

Assuming that 10.0% of a 100 W light bulb's energy output is in the visible range (typical for incandescent bulbs) with an avera

ge wavelength of 580 nm, and that the photons spread out uniformly and are not absorbed by the atmosphere, how far away (in km) would you be if 468 photons per second enter the 3.30 mm diameter pupil of your eye
Physics
1 answer:
Verizon [17]3 years ago
5 0

Answer:

Explanation:

10% of 100 W = 10 W .

energy of each photon = hν , h is plank's constant and ν is frequency

= hc / λ , c is velocity of light , λ is wavelength

wavelength given λ  = 580 x 10⁻⁹ m .

energy of each photon = 6.6 x 10⁻³⁴ x 3 x 10⁸ / 580 x 10⁻⁹

= .034137 x ⁻¹⁷ J

no of photons in 10 W

= 10 /  .034137 x ⁻¹⁷

= 292.9 x 10¹⁷

If d be the required distance

no of photons per unit area per second  at distance d

= 292.9 x 10¹⁷ / 4πd²

no of photons through the area of eye

= π x (1.65 x 10⁻³)² x 292.9 x 10¹⁷ / 4πd²

= 199.355 x 10¹¹ / d²

199.355 x 10¹¹ / d² = 468 ( given )

d² = 199.355 x 10¹¹ / 468

= .42597 x 10¹¹

= 42597 x 10⁶

d = 206.4 x 10³ m

= 206.3 km.

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Anettt [7]

Answer:

A   u = 0.36c      B u = 0.961c

Explanation:

In special relativity the transformation of velocities is carried out using the Lorentz equations, if the movement in the x direction remains

     u ’= (u-v) / (1- uv / c²)

Where u’ is the speed with respect to the mobile system, in this case the initial nucleus of uranium, u the speed with respect to the fixed system (the observer in the laboratory) and v the speed of the mobile system with respect to the laboratory

The data give is u ’= 0.43c and the initial core velocity v = 0.94c

Let's clear the speed with respect to the observer (u)

      u’ (1- u v / c²) = u -v

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      u (1 + u ’v / c²) = v - u’

      u = (v-u ’) / (1+ u’ v / c²)

Let's calculate

      u = (0.94 c - 0.43c) / (1+ 0.43c 0.94 c / c²)

      u = 0.51c / (1 + 0.4042)

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We repeat the calculation for the other piece

In this case u ’= - 0.35c

We calculate

       u = (0.94c + 0.35c) / (1 - 0.35c 0.94c / c²)

       u = 1.29c / (1- 0.329)

       u = 0.961c

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3 years ago
Which of the following is a quantitative observation?
liubo4ka [24]

The statement that is a quantitative observation is that bird has four different colors on it (option B).

<h3>What is a quantitative research?</h3>

A quantitative research is a systematic scientific investigation of quantitative properties and phenomena and their relationships, using statistical methods.

A quantitative observation has to do with numbers or numeric analysis.

This suggests that the statement that is a quantitative observation is that bird has four different colors on it.

Learn more about quantitative observations at: brainly.com/question/1434538

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Answer :

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2 years ago
A student uses 150 N to push a block of wood up a ramp at constant velocity of 2.6m/s. What is his power output?
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Answer:

P= 390 W

Explanation:

In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time.  Work  is a force F applied over a distance x. Matemathicaly it means

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