The momentum of a photon is given by the following relationship:
where
h is the Planck constant
is the photon wavelength
For the photon in our problem,
, so its momentum is
The electron must have the same momentum of this photon, and its momentum is given by (in the non-relativistic approximation)
where
m is the electron mass
v is its speed
Re-arranging this formula, we can calculate the electron speed:
And this velocity is quite small compared to the speed of light (
), so the non-relativistic approximation that we used for the electron's momentum is valid.
Answer:
r=0.127
Explanation:
When connected in series
Current = I
When connected in parallel
Current = 10 I
We know that equivalent resistance
In series R = R₁+R₂
in parallel R= R₁R₂/(R₂+ R₁)
Given that voltage is constant (Vo)
V = I R
Vo = I (R₁+R₂) ------------1
Vo = 10 I (R₁R₂/(R₂+ R₁)) -------2
From above equations
10 I (R₁R₂/(R₂+ R₁)) = I (R₁+R₂)
10 R₁R₂ = (R₁+R₂) (R₂+ R₁)
10 R₁R₂ = 2 R₁R₂ + R₁² + R₂²
8 R₁R₂ = R₁² + R₂²
Given that
r = R₁/R₂
Divides by R₂²
8R₁/R₂ = ( R₁/R₂)²+ 1
8 r = r ² + 1
r ² - 8 r+ 1 =0
r= 0.127 and r= 7.87
But given that R₂>R₁ It means that r<1 only.
So the answer is r=0.127
To solve this problem we will apply the concepts related to the principle of archimedes. for which we will summarize that the bearing force must be equivalent to the mass of the individual and the mass of the way. Said mass of wood will be expressed in terms of density and volume. Finally with the values found we will proceed to find the Volume of the wood and thus find the mass.
For the relation between density and Volume we have that,
Where given that,
Mass of woman, 
If the density of the wood is 60% the density of the water we will have to
Density of water, 
And density of wood is
Now the mass of the man can be expressed as
Mass of wood required is given by,
Therefore the minimum mass necessary to support a 70kg Woman is 105Kg.
D)
Density is equal to mass/volume, so in your case:
density=1.3/1000=0.0013 g/cm^3
A .Earthquakes
Explaination
