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3 years ago

A white dwarf is:______.

Physics

1 answer:

bija089 [108]3 years ago

6 0

Answer:

the exposed core of a dead star, supported by electron degeneracy pressure.

Explanation:

A white dwarf is a low luminosity exposed core of a dead star having mass comparable to the sun but volume comparable to the earth . So its density is very high . These stars have lost the capacity to generate energy through the process of fusion . Due to high gravitational energy , it goes on shrinking but ultimately balanced by electron degeneracy pressure. It is not a main sequence star as it has lost the power of fusion .

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Two resistors A and B are arranged in series in one branch of a parallel arrangement. The other branch contains a single resisto

Ganezh [65]

Answer:

Explanation:

A and B are in series , Total resistance = Ra + Rb

This resistance is in parallel with single resistor C

Equivalent resistance Re = Rc x ( Ra + Rb ) / [Rc + ( Ra + Rb )]

Now this combination is in series in single resistance D .

Total resistance = Rd + Re

= Rd + { Rc x ( Ra + Rb ) / [Rc + ( Ra + Rb )] }

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2 years ago

In a given chemical reaction the energy of the products is less than the energy of the reactants. Which statement is true for th

Westkost [7]

Answer:

B. Energy is released in the reaction.

7 0

3 years ago

An object is hung from a spring balance attached to the ceiling of an elevator cab. The balance reads 65 N when the cab is stand

lana66690 [7]

Answer:

(A) Reading will be 65 N

(B) Net force on the elevator will be 49.076 N

Explanation:

We have given the balance force = 65 N

Acceleration due to gravity $g=9.8m/sec^2$

We know that W=mg

So $65=m\times 9.8$

m = 6.632 kg

(a) In first case as the as the speed is constant so the force on the elevator will be 65 N

(B) In second case as the elevator is decelerating at a rate of $2.4m/sec^2$

So net acceleration = 9.8-2.4= $7.4m/sec^2$

So net force on elevator will be = m× net acceleration = 6.632×7.4 = 49.076 N

7 0

3 years ago

Given that ethylene has a λmax of 175nm, butadiene has a λmax of 220nm, and 2-methyl-1,3-butadiene has a λmax or 215nm, what is

Vika [28.1K]

The λmax of 2,3,4-trimethylhexatriene is 280 nm.

Ethylene has a λmax of 175nm.

Butadiene has a λmax of 220nm.

2-methyl-1,3-butadiene has a λmax or 215nm.

1,3,5-hexatriene has a λmax of 258nm.

Woodward's rules, sometimes known as Woodward-Fieser rules (after Louis Fieser) and named after Robert Burns Woodward, are a number of sets of empirically developed principles that aim to forecast the wavelength of the absorption maximum (max) in an ultraviolet-visible spectrum of a certain molecule.

By using the Woodward Fieser rule,

R- (Alkyl Group) .... +5 nm = 5 × 2 = 10

RO- (Alkoxy Group) .. +6 = 6 × 2 = 12

Adding 22nm to the λmax of 1,3,5-hexatriene as it has 2 alkyl groups and 2 alkoxy groups to form 2,3,4-trimethylhexatriene.

The λmax of 2,3,4-trimethylhexatriene is 280 nm.

Learn more about Woodward-Fieser here:

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1 year ago

Which statement correctly describes the electrons in a water molecule?. . A.Which statement correctly describes the electrons in

exis [7]

The statement “Electrons are pulled closer to the oxygen atom” correctly describes the electrons in a water molecule. The correct answer between all the choices given is the second choice or letter B. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.

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3 years ago

Read 2 more answers