the spontaneous emission rate for the 21-cm hyperfine line in hydrogen (section 7.5) can be obtained from equation 11.63, except that this is a magnetic dipole transition, not an electric one
p->1/c m=1/c (1|(πe+πp)|0)
where
πe=-e/mese, πp=5.59e/2mp sp
are the magnetic moments of the electron and proton (Equation 7.89), and |0〉, |1〉are the singlet and triplet configurations (Equations 4.175 and 4.176). Because mp ≫ me, the proton contribution is negligible, so
a=w30 e2/3π€0hc5m2e|(1|se|0)|2
Work out |〈1| Se |0〉|2 (use whichever triplet state you like). Put in the actual numbers, to determine the transition rate and the lifetime of the triplet state. Answer: 1.1 × 107 years.

Answer:

steam

Explanation:

particles move faster in a gas than in a liquid or solid

Answer:

Mass, in physics, quantitative measure of inertia, a fundamental property of all matter. It is, in effect, the resistance that a body of matter offers to a change in its speed or position upon the application of a force. The greater the mass of a body, the smaller the change produced by an applied force.

Explanation:

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Answer:

Mass, in physics, quantitative measure of inertia, a fundamental property of all matter. It is, in effect, the resistance that a body of matter offers to a change in its speed or position upon the application of a force. The greater the mass of a body, the smaller the change produced by an applied force.

Explanation:

Hope that helps! :)

Answer:

Explanation:

True

Answer:

True..................

Answer:

c

Explanation:

this is because newton's first law of motion states that every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it

so if the resultant force on the refrigerator is 0N, but it was initially moving, it will continue in its motion in a straight line.

it will not change direction since it will continue in its uniform motion.

hope this helps

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Answer:

Increase, same, same

Explanation:

Answer:

you want to know newtons first law here.

Explanation:

An object that is at rest stays at rest or stays in motion.

Answer:

Yes, the magnet force will cause the motor rotate through a full rotation. So the friend who claims to have built a motor by attaching a shaft to the core of a galvanometer and removing the spring is correct.

Answer:

v = 150 m/s

Explanation:

Given that,

The acceleration of the ball, a = 10 m/s²

Time, t = 15 s

We need to find the increase in ball's velocity. When it is dropped its initial velocity is equal to 0. Let v be the velocity,

v = u+at

v = 0 +10(15)

v = 150 m/s

So, the ball's final velocity is 150 m/s.

Answer:

The highest surface part of a wave is called the crest, and the lowest part is the trough. The vertical distance between the crest and the trough is the wave height. The horizontal distance between two adjacent crests or troughs is known as the wavelength.

I hope it's helpful!

Answer:

this much I think 101.9716212978

Answer:

approximately 102kg

Explanation:

1 kg on the surface of the Earth weighs 9.80665 N

1000 N = 1000/9.80665 kg = 102 kg

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Thank you for that information.  If we know her mass and kinetic energy, then we don't need any of that other business about the height of the slope, her skiing ability, the friction of the snow, what she uses to wax her skis, the color of her parka, or what she had for lunch at the chalet.  The mass and kinetic energy are enough to answer the question.

Kinetic Energy = (1/2) · (mass) · (speed)²

31,360 J = (1/2) · (80 kg) · (speed)²

speed² = (31,360 J) / (40 kg)

speed² = 784 m²/s²

speed = 28 m/s

Answer:

It will apply the greatest pressure of an area of 1.

Explanation:

To find pressure use the formula P = F/A

P = 100/1

P = 100

Answer:

10 N / cm^2

Explanation:

The Formiula is P = F / A

P = presure

F = Force in Newtons

A = area.

The answer is the smaller the area the larger the pressure.

The smallest area you have given us is 10 cm^2

The Pressure = 100N / 10 cm^2

Pressure = 10 N/cm^2  

Note: the units are not exactly standard units, but I've given the answer the way the question offers the units.

Answer:

False

Explanation:

There are 3 states of matter, and all states have molecules. These molecules vibrate in different speeds, depending on the mass, weight, and stae off matter of the object.

Answer:

to find the displacement, or delta x (change in position) on a velocity graph, you can find the area under the line on the graph: between 1 and 8 seconds, the dog was going at 5m/s, so 5m/s x 8s=40m, for the second part, you have to find the area of both a triangle and a rectangle, so the rectangle would be 5m/s x 5s=25m and the area under the triangle would be (5m/s x 5s)/2=25m/2=12.5m -you divide by 2 because it's a triangle

-afterwards, you would add the area of the 2 sections together, so 40m+25m+12.5m=77.5m

Explanation:

Explanation:

A circuit breaker is an automatic switch that cut off current in a circuit when the current become too large. When the current in a circuit increases, the strength of the electromagnet will increase in accordance; this will pull the soft iron armature towards the electromagnet.

Answer:

Biodiversity is the variety and variability of life on Earth. Biodiversity is typically a measure of variation at the genetic, species, and ecosystem level. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity.

Explanation:

hope it helped <3

Answer:

[tex]A_{1}[/tex] = 0.2 [tex]m^{2}[/tex]

Explanation:

The pressure on the pistons is given as;

Pressure = [tex]\frac{Force}{Area}[/tex]

So that,

Pressure on the small piston = [tex]\frac{F_{1} }{A_{1} }[/tex] and Pressure on the large piston = [tex]\frac{F_{2} }{A_{2} }[/tex]

Thus,

[tex]\frac{F_{1} }{A_{1} }[/tex] = [tex]\frac{F_{2} }{A_{2} }[/tex]

Given that: [tex]F_{1}[/tex] = 100 N, [tex]F_{2}[/tex] = 2000 N, [tex]A_{2}[/tex] = 4 [tex]m^{2}[/tex].

[tex]\frac{100}{A_{1} }[/tex] = [tex]\frac{2000}{4}[/tex]

[tex]A_{1}[/tex] = [tex]\frac{100*4}{2000}[/tex]

    = [tex]\frac{400}{2000}[/tex]

    = 0.2

[tex]A_{1}[/tex] = 0.2 [tex]m^{2}[/tex]

The area of the small piston is 0.2 [tex]m^{2}[/tex].

Answer:

you know the answer i answered it before on a question 0-0

Explanation:

Answer:

Em waves from the sun d

Explanation:

Answer:

The answer is photosynthesis

Explanation:

Answer:

39.2m/s

Explanation:

V = 0

V = u - gt

0 = u - 9.8×4

u = 39.2

Answer:

1/4

Explanation:

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Answer:

G

Explanation:

Answer:

a

Explanation:

aaajsjdndndnjxjzkskdjawuj

Answer:

An earthquake is a sudden shaking movement of the surface of the earth. It is known as a quake, tremblor or tremor. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities. ... An earthquake is measured on Richter's scale.

Answer:

12 neutrons

Explanation:

The number of protons also shows the atomic number. Therefore the element in question is Krypton (Kr), which also is a noble gas.

Neutrons = Mass number - protons - electrons

Here neutrons = 84 - 36 - 36 = 12

Answer: the last one

Explanation:

Answer:

C

Explanation:

Answer:

answer is option (c) child labour

Answer:

Shadow

Explanation:

Shadow is a area of darkness.

When sunlight falls on an object ot blocks the light from getting onto the surface . Hence, as light does not falls on that region it is dark. Hence, the shadow is the area of darkness.

Answer:

shadow is a area of darkness

Answer:

The answer is B. 8000.

Explanation:

She gained 10,000J , but when she reached the bottom she was at 2,000J. All you need to do is 10,000-2,000 and you get 8,000. So the answer is 8,000J.