The fossil record shows scientists that

Physics

2 answers:

erastova [34]3 years ago

4 0

tells the story of the past and shows the evolution of forms over millions of years.

Aleonysh [2.5K]3 years ago

3 0

Answer:

The fossil record tells the story of the past and shows the evolution of forms over millions of years

Explanation:

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X rays of wavelength 0.0169 nm are directed in the positive direction of an x axis onto a target containing loosely bound electr

mamaluj [8]

Answer:

a) 4.04*10^-12m

b) 0.0209nm

c) 0.253MeV

Explanation:

The formula for Compton's scattering is given by:

$\Delta \lambda=\lambda_f-\lambda_i=\frac{h}{m_oc}(1-cos\theta)$

where h is the Planck's constant, m is the mass of the electron and c is the speed of light.

a) by replacing in the formula you obtain the Compton shift:

$\Delta \lambda=\frac{6.62*10^{-34}Js}{(9.1*10^{-31}kg)(3*10^8m/s)}(1-cos132\°)=4.04*10^{-12}m$

b) The change in photon energy is given by:

$\Delta E=E_f-E_i=h\frac{c}{\lambda_f}-h\frac{c}{\lambda_i}=hc(\frac{1}{\lambda_f}-\frac{1}{\lambda_i})\\\\\lambda_f=4.04*10^{-12}m +\lambda_i=4.04*10^{-12}m+(0.0169*10^{-9}m)=2.09*10^{-11}m=0.0209nm$

c) The electron Compton wavelength is 2.43 × 10-12 m. Hence you can use the Broglie's relation to compute the momentum of the electron and then the kinetic energy.

$P=\frac{h}{\lambda_e}=\frac{6.62*10^{-34}Js}{2.43*10^{-12}m}=2.72*10^{-22}kgm\\$

$E_e=\frac{p^2}{2m_e}=\frac{(2.72*10^{-22}kgm)^2}{2(9.1*10^{-31}kg)}=4.06*10^{-14}J\\\\1J=6.242*10^{18}eV\\\\E_e=4.06*10^{-14}(6.242*10^{18}eV)=0.253MeV$

5 0

3 years ago

An office heater puts out 2050 btus of energy in the form of heat per hour. given that 1 btus =1.055 kj, how many megajoules of

ivolga24 [154]

<span>Assuming continuous operation (24/7), we can say that

Energy produced : Energy per hour * 24 (number of hours in a day) - 365 (number of days in a year.

Energy per hour: 2050 * 1.055 = 2162.75 kg.

So, we proceed to calculate the results

E: 2162.75 * 24 * 365 = 18,945,690 kj per year.

Now, we transform kj to megajoule, remembering that kilo is 10*3 and mega is 1'*6, so we divide the result by 1,000 in order to get the results in megajoules, and the answer would be:

18,945.69 megajoules can be produced per year.</span>

4 0

3 years ago

Is there a sound loud enough to kill a person ?

shepuryov [24]

In space there is. Items such as a supernova will instantly end your life.

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3 years ago

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A railroad freight car, mass 15,000 kg, is allowed to coast along a level track at a speed of 2.0 m/s. It collides and couples w

gayaneshka [121]

Answer:

The speed of the two cars after coupling is 0.46 m/s.