Physics: Problems and Solutions

AdityaSingh7777 AdityaSingh7777 13 November 2021


E = mc² The Most Important & Famous Physical Equation

Read Full Post
Granpa Granpa 1 May 2019

Primary colors

The primary colors that the brain (not the retina) perceives are


combining these gives the secondary colors


One can see that these secondary colors are intermediate between the primary colors

One would assume then that combining a primary color and a secondary color would result in a color intermediate between the primary and the secondary. And indeed most do. Except for cyan. Cyan is produced by combining blue light and green light but the color we perceive is not intermediate between blue and green.

The color we perceive as cyan is clearly a combination of blue and something. But what that something is is just not clear.

in a bird's cone cells.]]

I suggest that there were originally four primary colors and that cy…

Read Full Post
Granpa Granpa 14 April 2019

Natural units

See also: Dimensional analysis and Nondimensionalization

In physics, natural units are physical units of measurement based only on universal physical constants. For example, the elementary charge e is a natural unit of electric charge, and the speed of light c is a natural unit of speed.

  • 1 Fundamental units
    • 1.1 Uncertainty principle
  • 2 References
  • 3 External links

A set of fundamental dimensions is a minimal set of units such that every physical quantity can be expressed in terms of this set and where no quantity in the set can be expressed in terms of the others.

  • Uncertainty principle
  • Gaussian function

  • The Spectrum of Riemannium
  • Stoney Scale and Large Number Coincidences

Read Full Post
Granpa Granpa 7 March 2018


Earth's weather is primarily driven by rising air in three Low-pressure areas.

  • The northern hemisphere polar front.
    • Extratropical cyclones form along the front and move eastward at 12-15 m/s (43-54 km/h) and last 3-5 days. (3600-6000 km)
  • The Intertropical Convergence Zone. Sometimes, a double ITCZ forms, with one north and one south of the Equator.
    • Tropical cyclones (Hurricanes) form here and move westward.
  • The southern hemisphere polar front.
    • Extratropical cyclones form along the front and move eastward

And to a lesser extent by descending air in two High-pressure areas:

  • Northern hemisphere subtropical ridge (horse latitudes)
    • The Sahara desert is here.
  • Southern hemisphere subtropical ridge (horse latitudes)
    • The Kalahari (in south Africa), the Atacam…
Read Full Post
Granpa Granpa 9 February 2018

Superconductors and supersolids

Many people wonder how it is possible for a current of electrons to flow forever through a superconductor without any loss. The simplest explanation is that it doesn't. Instead a field is set up inside the superconductor which behaves as though charge was flowing.

The same is true of supersolids except that instead of behaving as though charge was flowing it behaves as though inertial mass was flowing. If we could learn to control this then we could create reaction wheels that have no moving parts.

Read Full Post
Granpa Granpa 9 February 2018


The triangle in the diode symbol points in the forward direction, i.e. in the direction of conventional current flow. Electrons flow in the opposite direction.

An n-type semiconductor only conducts negatively charged electrons. A p-type semiconductor only conducts positively-charged holes.

When the diode is forward biased current flows easily and electrons and holes move toward each other and combine at the junction. In the case of a light emitting diode the combining of electrons and holes results in the creation of light.

When the diode is reverse biased current doesn't flow at all. However, in the case of a photodiode current can be induced to flow by shining a light on the junction. When the light is absorbed electrons and holes are created at the…

Read Full Post
Gringo300 Gringo300 14 December 2017

gravity and gravitation

I'm unclear on whether or not there is a distinction between gravity and gravitation.

Read Full Post
Granpa Granpa 15 August 2017

Coronal heating problem

Why is the Sun's Corona so much hotter than the Sun's surface? The coronal heating problem in solar physics relates to the question of why the temperature of the Sun's corona is millions of kelvin higher than that of the surface. The high temperatures require energy to be carried from the solar interior to the corona by non-thermal processes, because the second law of thermodynamics prevents heat from flowing directly from the solar photosphere, or surface, at about 5800 K, to the much hotter corona at about 1 to 3 MK (parts of the corona can even reach 10 MK).

I believe that vibrating atoms in the Sun's core emit Gravitational Waves. The absorption of this energy corresponds to a Forbidden Transition therefore these waves pass through the…

Read Full Post
Granpa Granpa 15 August 2017

Spatial structure of the electron

I am not Victor V. Demjanov.

Experiments performed in order to reveal fundamental differences between the diffraction and interference of waves and electrons

Victor V. Demjanov
(Submitted on 20 Feb 2010)

Diffraction patterns of electrons are believed to resemble those of electromagnetic waves (EMW). I performed a series of experiments invoked to show that the periodicity of peaks in the diffraction diagram of electrons is concerned with the periodicity of the arrangement of scattering centers in the diffraction grating in combination with the supposed character of the spatial structure of the electron as a system of regularly spaced concentric shells of elasticity.

I started from the experiment on the diffraction …

Read Full Post
Granpa Granpa 15 August 2017

Brown dwarfs and degenerate matter

The pressure that an electron orbital can resist without becoming degenerate = 1/radius^6.
(Except for nondegenerate matter which is 64 times greater)
Therefore the maximum radius that a solid astronomical object can become before its core collapses depends only on its atomic mass.
This is why all planets from 1 to 52 jupiter masses are approximately the same size

Atoms of degenerate matter are four times smaller than non degenerate matter. Double degenerate atoms are eight times smaller. Triple degenerate are 16 times smaller.

Image shows 1 diatomic hydrogen molecule next to 2 monatomic helium atoms
A hydrogen molecule and a helium atom both have a charge of 2 and are therefore the same size.
Outer electron shell is triple degenerate.
Inner ele…

Read Full Post
Granpa Granpa 14 August 2017

Hypercomplex numbers

Complex number = a + bi
i^2 = -1
a and b are the coefficients.

Quaternion = hypercomplex = complex number with complex coefficients = (a+bi)1 + (c+di)j
j^2 = -1
ij = -ji = k

Biquaternion = quaternion with complex coefficients.

Quaternions find uses in both theoretical and applied mathematics, in particular for calculations involving three-dimensional rotations such as in three-dimensional computer graphics, computer vision and crystallographic texture analysis. In practical applications, they can be used alongside other methods, such as Euler angles and rotation matrices, or as an alternative to them, depending on the application.

Quaternions have had a revival since the late 20th century, primarily…

Read Full Post
Granpa Granpa 14 August 2017

Algebraic structures

A magma (or groupoid) is a set with a single closed binary operation (addition).

a + b = c

A semigroup is a magma where the addition is associative.

a + (b + c) = (a + b) + c

A monoid is a semigroup with an additive identity element.

a + 0 = a

A group is a monoid with additive inverse elements.

a + (-a) = 0

An abelian group is a group where the addition is commutative.

a + b = b + a

A pseudo-ring is an abelian group that has a second closed, associative, binary operation (multiplication) as well.

a * (b * c) = (a * b) * c
And these two operations satisfy a distribution law.
a(b + c) = ab + ac

A ring is a pseudo-ring that has a multiplicative identity (see below)

a * 1 = a

A commutative ring is a ring where multiplication commutes,

a * b = b * a

A field is a commutative ring…

Read Full Post
Granpa Granpa 14 August 2017


Read Full Post
Granpa Granpa 14 August 2017

Magnetic field in 4 spatial dimensions

Magnetic field in 4 spatial dimensions

In ordinary 3D space the magnetic field forms a ring around a moving charge which is everywhere at right angles to the electric field and the direction of motion of the charge.

But if the charge were moving in the direction of a fourth spatial Dimension then the magnetic field would form a 3D shell completely enclosing the charge. The magnetic field would no longer be a vector field but rather would be a bivector field.

In three dimensions light consists of oscillating electric and magnetic (vector) fields which are at a right angle to each other and to the direction of propagation of the light. One dimension is the electric field. Another dimension is the magnetic field. The third dimension is the d…

Read Full Post
Granpa Granpa 14 August 2017


Now what would have to be true for an electron to fit inside a Neutron? Lets see.

Angular momentum of electron = (planks constant)/(2pi) Relativistic angular momentum = γmvr Relativistic centripetal force = γmv^2/r

Gamma*(electron mass)c(10^-14 m)=(planks constant)/(2pi) solve for gamma Wolfram says gamma = 38.6

38.6*(electron mass)*(velocity of light)^2/(10^-14 m) Wolfram says force = 316 newtons

The force between 2 electrons at that distance is ( Coulomb's constant )*(electron charge)^2/(10^-14 m)^2 Wolfram says 2.3 newtons

According to those equations the force holding the electron inside the neutron is 137 times stronger than electrostatic repulsion would be at that distance Which means the strong force is 10 billion times stronger tha…

Read Full Post
Granpa Granpa 14 August 2017

Proper velocity

I never realized how useful proper velocity is. Not only is it useful at both low speed and high speeds but it equals momentum per unit mass at any speed

By grouping γ with v in the expression for relativistic momentum p, proper velocity also extends the Newtonian form of momentum as mass times velocity to high speeds without a need for relativistic mass.

proper acceleration is the rate of change of proper velocity with respect to coordinate time. proper acceleration α and coordinate acceleration a are related through the Lorentz factor γ by α=γ^3a.

Read Full Post
Granpa Granpa 14 August 2017

Uranium nucleus

There is no strong force. When two protons or proton shells move toward each other each one puffs up so that the total electrostatic energy of the overall system decreases. The system therefore naturally moves toward the state of lowest energy and the 2 proton shells merge.

The size of each proton shell is quantum mechanically coupled to the distance between them. There is no classical analogue.

In reality there's a few neutrons involved too. But the general idea is the same.

The maximum range of the strong force is about 10 fm.

Two protons at rest 10 fm from each other will accelerate away from each other until each has a kinetic energy of about 72,000 electron volts.*%281+electro…

Read Full Post
Granpa Granpa 14 August 2017

Gamma-ray bursts

Short grb = 0.3 sec
Intermediate grb = 1.5 sec
long grb = 30 sec

Radius of largest White Dwarf = 0.13 light seconds

Diameter of neutron = 2 fm
Diameter of tetraneutron = 4 fm

The density of a neutron star = (1.5*10^14 g/cm^3)

This is the density of close packed tetraneutrons

A 1.4 solar mass neutron_star is 11.5 km in radius.
Gravitational binding energy of a neutron star is 0.151 solar mass which is one tenth of its rest Mass

(3 * G * (1.4 solar mass)^2/(5 * 11.5 km))/c^2 = 0.151 solar masses
Surface gravity = 1.43270128 * 10^11 g's
Core pressure = 1.212 * 10^28 bar

When the core of the 1.4 solar mass neutron star finally collapses the energy released by the strong force (not gravity) in the collapse is converted to passive gravitational_mass but wit…

Read Full Post
Granpa Granpa 14 August 2017


Earth differentiated into gabbro (upper mantle) and peridotite (lower mantle). Earths moon Theia differentiated even further into granodiorite and dunite (olivine).

3 billion years ago Theia's decaying orbit reached the Roche limit and over the next 1 billion years slowly deposited all of its mass onto a ring of mountains circling the earth's equator.

First the ice on its surface was deposited. This formed Earths ocean. Since Earth had no continents at that time the surface of the Earth was completely flooded.

Then the granodiorite was deposited. The granodiorite metamorphosed into the various rocks of the continental crust.

Then 2.4 billion years ago the dunite was deposited. This created the banded iron formations. The dunite sank to the bo…

Read Full Post
Granpa Granpa 14 August 2017

Lunar recession

There is geological and paleontological evidence that Earth rotated faster and that the Moon was closer to Earth in the remote past. Tidal rhythmites are alternating layers of sand and silt laid down offshore from estuaries having great tidal flows. Daily, monthly and seasonal cycles can be found in the deposits. This geological record indicates that 620 million years ago there were 400±7 solar days/year.

The current rate of lunar recession which has been measured very accurately by mirror's placed on the moon indicates that there should have been 426 days in a year 620 million years ago. The usual explanation for the discrepancy is that the moon was receding more slowly in the past. This makes no sense. If anything the moon should have b…

Read Full Post
Granpa Granpa 14 August 2017

Formation of the Solar System

Image below shows four equipotentials of a rapidly spinning 50 Jupiter mass protostar. The north pole is up. The south pole is down. The equator reaches orbital velocity.

Planets form 4 at a time from material spun off the equator. A pair of large planets and a pair of small planets.
At first all 4 of the planets are in the same orbit but eventually they end up in orbits that look like this:

Over time the orbits are circularized.

All masses are in units of 10^22 kg

Protosun 9,500,000

Jupiter 189,800
Satyrn 56,830
Neptune 10,240
Ouranos 8,681


Earth 597
Venus 487
Mars 64
Mercury 33

Jupiter has four large moons too :

Ganymede 15
Callisto 10
Io 9
Europa 5

Ouranos also has four large moons

Titania 0.35
Oberon 0.3
Ariel 0.135
Umbriel 0.117

Only two issues:
1) O…

Read Full Post
Granpa Granpa 14 August 2017


See also User_blog:Granpa/Theia





1st density is at the surface. 2nd is at depth.
Volume of Moon = 1
Density of liquid iron = 6.3 g/cm3 at 6000 C
Density of solid iron (fcc) = 8.6 g/cm3
Density of Inner core = 8.587 * 27 = 231.85
Read Full Post
Granpa Granpa 14 August 2017

Atomic radius

See w:c:chemistry:User_blog:Granpa/Quantum_numbers_and_the_Zeeman_effect

Read Full Post
Granpa Granpa 13 August 2017



Read Full Post
Dinoenthusiastguy Dinoenthusiastguy 30 May 2016

Rebooting again!

I am once again going to try to reboot this wiki and adopt it. Anyone with me? --Dinoenthusiastguy (talk) 16:24, May 30, 2016 (UTC)

Read Full Post
Dinoenthusiastguy Dinoenthusiastguy 24 November 2014

Rebuilding wiki

Hi everyone! I don't know if anyone is reading this, but if you are, please reply. This wiki seems to be almost completely abandoned aside from Darkenkaul and myself. If anyone wants to help the wiki please do so, especially if you are an admin. If no admins can be found, I'll try to adopt it. In the mean time, there is lots of work to be done. Help wanted! --Dinoenthusiastguy (talk) 04:30, November 24, 2014 (UTC)

Read Full Post
Drakenkaul Drakenkaul 19 August 2014

Physics Relative Velocity Concept Trouble

I always had trouble with relative velocity problems in two dimensions. Can anyone help me understand the "Man Moving in Rain" relative velocity concept. Also I sometimes get into trouble when I face questions that contain the thing about a man tring to cross a river and all that river flow making him drift right(or left) and then calculating the velocity with respect to ground etc. etc.

Read Full Post