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Alexxandr [17]
3 years ago
8

Approximately what core temperature is required before hydrogen fusion can begin in a star?

Physics
1 answer:
valkas [14]3 years ago
8 0

Answer:

The temperature required is near about 3 million kelvin

Explanation:

The brilliance of the star results from the nuclear reaction that take place in the core of the star and radiate a huge amount of thermal energy resulting from the fusion of hydrogen into helium.

For this reaction to take place, the temperature of the star's core must be near about 3 million kelvin.

The hydrogen atoms collide and starts and the energy from the collision results in the heating of the gas cloud. As the temperature comes to near about 1.5\times 10^{7 {\circ}C, the nuclear fusion reaction takes place in the core of the gas cloud.

The huge amount of thermal energy from the nuclear reaction gives the gas cloud a brilliance resulting in a protostar.

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Light travels in a straight line at a constant speed of 3,0 x 108 m/s for 4,1
zepelin [54]

Answer:

As the velocity of light is constant so the acceleration of the light is equal to zero.

a= dv/dt

Explanation:

4 0
3 years ago
How do I do this physics problem about potential energy and kinetic energy?
larisa86 [58]

Ok i apologise for the messy working but I'll try and explain my attempt at logic

Also note i ignore any air resistance for this.

First i wrote the two equations I'd most likely need for this situation, the kinetic energy equation and the potential energy equation.

Because the energy right at the top of the swing motion is equal to the energy right in the "bottom" of the swing's motion (due to conservation of energy), i made the kinetic energy equal to the potential energy as indicated by Ek = Ep.

I also noted the "initial" and "final" height of the swing with hi and hf respectively.

So initially looking at this i thought, what the heck, there's no mass. Then i figured that using the conservation of energy law i could take the mass value from the Ek equation and use it in the Ep equation. So what i did was take the Ek equation and rearranged it for m as you can hopefully see. Then i substituted the rearranged Ek equation into the Ep equation.

So then the equation reads something like Ep = (rearranged Ek equation for m) × g (which is -9.81) × change in height (hf - hi).

Then i simplify the equation a little. When i multiply both sides by v^2 i can clearly see that there is one E on each side (at that stage i don't need to clarify which type of energy it is because Ek = Ep so they're just the same anyway). So i just canceled them out and square rooted both sides.

The answer i got was that the max velocity would be 4.85m/s 3sf, assuming no losses (eg energy lost to friction).

I do hope I'm right and i suppose it's better than a blank piece of paper good luck my dude xx

4 0
3 years ago
Branches of sicence​
Sonja [21]

Answer:

physical science

earth science and life science

5 0
3 years ago
Read 2 more answers
A parallel-plate capacitor has square plates that are 8.00cm on each side and 4.20mm apart. The space between the plates is comp
Sergeu [11.5K]

Answer:

U=1.29\times 10^{-7}\ J

Explanation:

Given that

a= 8 cm (square)

A= a ² = 64 cm²

d= 4.2 mm

d₁= 2.1 mm  ,K₁= 4.7

d₂=2.1 mm  , K₂=2.6

We know that capacitance given as

C_1=\dfrac{K_1\varepsilon _oA}{d_1}

C_1=\dfrac{4.7\times 8.85\times 10^{-12}\times 64\times 10^{-4}}{2.1\times 10^{-3}}

C_1=1.26\times 10^{-10}\ F

C_2=\dfrac{K_2\varepsilon _oA}{d_2}

C_2=\dfrac{2.6\times 8.85\times 10^{-12}\times 64\times 10^{-4}}{2.1\times 10^{-3}}

C_2=0.701\times 10^{-10}\ F

Net capacitance

C=\dfrac{C_1C_2}{C_1+C_2}

C=\dfrac{1.26\times 10^{-10}\times 0.701\times 10^{-10}}{1.26\times 10^{-10}+0.701\times 10^{-10}}\ F

C=4.5\times 10^{-11}\ F

We know that stored energy given as

U=\dfrac{CV^2}{2}

V= 76 V

U=\dfrac{4.5\times 10^{-11}\times 76^2}{2}\ J

U=1.29\times 10^{-7}\ J

3 0
3 years ago
Magnesium is a highly flammable element which is easily combustible in the presence of oxygen:
NemiM [27]

4 atoms

Explanation:

On the product side, we expect to find 4 atoms of the product.

    An atom is the smallest indivisible particle that takes part in a chemical reaction.

    An element is a distinct substance that cannot be split-up into simpler substances. Such substances consist of only one kind of atom.

    In this reaction we have:

       2 elements:             Mg                O

on the reactant side:

   We have two moles of Mg:   2 atoms of Mg

            1 mole of oxygen gas:   2 atoms of O

                             total atoms:    4 atoms

According to the law of conservation of matter "in a chemical reaction, matter is neither created nor destroyed".

We expect to find 4 atoms of products which is MgO on the product side.

              2Mg + O₂ →  2MgO + heat

Learn more:

Conservation of matter brainly.com/question/2190120

#learnwithBrainly

     

   

       

3 0
3 years ago
Read 2 more answers
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