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dmitriy555 [2]
3 years ago
7

A 100 watt bulb emits monochromatic light of wavelength 400 nm. Calculate the number of photons emitted per second by the bulb.

Chemistry
1 answer:
umka21 [38]3 years ago
4 0

Answer:

f = 7.5 E14 s-1

Explanation:

energy emitted by photon:

  • E = h.c / λ.......(1)
  • E = h.f......(2) Planck-Einstein

∴ λ = (400nm)(m/1 E9 nm) = 4.00 E-7 m

∴ h ( Planck's constant) = 6.626070150 E-34 J.s

∴ c (velocity of light) = 3.00 E8 m/s

∴ f (frequency): photon/s

If (1) = (2):

⇒ f = c / λ = E / h

⇒ f = (3.0 E8 m/s) / ( 4.00 E-7 m) = 7.5 E14 s-1

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Answer: As the temperature decreases or pressure increases substances move toward the solid state. Solids have a definite shape and a definite volume due to the fact that their particles are relatively close together and are merely vibrating, contrary to popular convention, the particles of a solid are moving.

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3 years ago
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Answer:

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I hope this helps you!  

Have a great day

7 0
3 years ago
Convert the following
beks73 [17]
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3 years ago
Calculate the decrease in temperature (in Celsius) when 2.00L at 21.0*C is compressed to 1.00.
Anna71 [15]

Decrease in temperature is -126.0°C

<u>Explanation:</u>

Using Charles law we can set up the equation as,

V₁/T₁ = V₂/T₂

(2.00 L) / 294.0 K) = (1.00 L) / (x)

cross multiply to get:

2x = 294

2x/2 = 294/2

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Now kelvin is converted into Celsius by subtracting 273 from 147 as,

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8 0
4 years ago
You have two beakers. One beaker contains 100 mL of NaOH (a strong base); the other contains 100 mL of aqueous Na3PO4 (a weak ba
Ilya [14]

Answer:

D. If the pH of NaOH is 12, then that of Na₃PO₄ solution has to be lesser than 12.

Explanation:

In this problem, we are comparing the pH of a strong base to a weak base. A strong base is one that ionizes completely in aqueous solutions where as a weak base ionizes slightly.

The pH scale is good tool for measuring the acidity and alkalinity of various substances. It ranges from 1 - 14;

   

      1                                      7                                               14

                         ←                                       →

      increasing acidity                          increasing alkalinity

                                        neutrality

Strong bases have their pH value close to 14 and weak bases are close to 7.

Since Na₃PO₄ is a weak base, it will have lesser pH value compared to a strong base such as NaOH

6 0
4 years ago
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