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telo118 [61]
3 years ago
13

A laser produces 20.0 mW of red light. In 1 hour, the laser emits 2.29 X 10^20 photons. What is the wavelength of the laser?

Physics
1 answer:
Butoxors [25]3 years ago
8 0
Using Planck's equation,

E = nhc / λ

Also, Power = Energy / time
E = 20 x 10⁻³ x 60 x 60
E = 108 J

108 = (2.29 x 10²⁰ x 6.63 x 10⁻³⁴ x 3 x 10⁸) / λ
λ = 4.22 x 10⁻⁷ m
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A tree loses water to the air by the process of transpiration at the rate of 110 g/h. This water is replaced by the upward flow
Ksivusya [100]

Answer:

The answer is 1.87nm/s.

Explanation:

The 110g/hr  water loss must be replaced by 110g/hr of sap. 110g of sap corresponds to a volume of  

110g \div \dfrac{1040*10^3g}{1*10^6cm^3}  = 106cm^3

thus rate of sap replacement is

106cm^3/hr = 106*10^{-6}m^3/3600s  = 2.94*10^{-8}m^3/s

The volume of sap in the vessel of length x is

V = Ax,

where A is the cross sectional area of the vessel.

For 2000 such vessels, the volume is

V = 2000Ax

taking the derivative of both sides we get:

\dfrac{dV}{dt} = 2000A \dfrac{dx}{dt}

on the left-hand-side \dfrac{dx}{dt} is the velocity v of the sap, and on right-hand-side \dfrac{dV}{dt}  = 2.94*10^{-8}m^3/s; therefore,

2.94*10^{-8}m^3/s=2000Av

and since the cross-sectional area is

A = \pi (\dfrac{100*10^{-3}m}{2} )^2 = 7.85*10^{-3}m^2;

therefore,

2.94*10^{-8}m^3/s =2000(7.85*10^{-3}m^2)v

solving for v we get:

v = \dfrac{2.94*10^{-8}m^3/s}{2000(7.85*10^{-3}m^2)}

\boxed{v =1.875*10^{-9}m/s = 1.875nm/s}

which is the upward speed of the sap in each vessel.

8 0
3 years ago
Why are infrared waves located between microwaves and visible light on the electromagnetic spectrum?
dangina [55]

Answer: The infra red waves is located between microwave and visible light based on their WAVELENGTH and FREQUENCY of occurrence.

Explanation:

Electromagnetic waves are those waves that do not require or need a material medium for its propagation, but they are able to travel through a vacuum. They exhibit or show all properties associated or connected with light. They are undeflected in electric and magnetic fields. These electromagnetic waves are arranged in order of their FREQUENCY and WAVELENGTHS which is known as ELECTROMAGNETIC SPECTRUM.

FREQUENCY is defined as the number of cycles which the wave completes in one second and is measured in Hertz(Hz). While WAVELENGTH is defined as the distance between two successive crests or troughs of waves which is measured in meter (m).

The electromagnetic spectrum is made up of the following rays which is arranged from the biggest wavelengths to the smallest:

--> Radiowaves

--> microwave :

--> infrared rays:

--> visible light:

--> ultraviolet rays

--> x-rays and

--> Gamma rays.

According to the arrangement of the spectrum above, the microwave has a higher wavelength and frequency than the infrared rays, while the visible light has a lower wavelength and frequency than the infrared rays.

3 0
3 years ago
What is your basal metabolism
Arada [10]
It's the energy your body spends to just keep you breathing and your heart beating ... just being alive, without trying to DO anything.
5 0
3 years ago
Which is true about light and heat?
Snowcat [4.5K]

My best guess is c) Dark colors reflect less radiation making them warmer.

hope this helps!

5 0
3 years ago
Read 2 more answers
What is the numeric value of a mole for atoms or molecules?
Talja [164]

Answer:

6.02×10²³

Explanation:

Mole measures the number of particles in a specific substance. The numeric value of a mole for atom or molecules is approximately 6.02×10²³ atoms or molecules.

5 0
3 years ago
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