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2 years ago

What is the outcome of a star that runs out of hydrogen

Physics

1 answer:

givi [52]2 years ago

3 0

<h2>Answer: The nucleus becomes entirely helium.</h2>

To shine, the stars transform their hydrogen into helium by means of nuclear fusion. When at half of its life a star is without hydrogen, the nucleus becomes entirely helium and the star declines, becoming colder and brighter due to the energy generated by the nuclear reactions, then the star begins to contract.

Nevertheless, if the star is bigger, this helium will be also consumed and the nucleus transformed in Carbon, then in Oxigen, and so on. Being the last transformation Iron until the star delivers all its energy.

Note this process will depend on how massive the star is.

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To what temperature must you raise a silver wire (c = 0.0038), originally at 20.0°C, to double its resistance, neglecting any ch

balu736 [363]

Answer:

$T=283^{\circ}C$

Explanation:

Given a material with temperature coefficient of resistance c, the equation that relates the resistance $R_0$ at temperature $T_0$ and the resistance $R$ at temperature $T$ is

$\frac{R-R_0}{R_0}=c(T-T_0)$

We want to double our resistance, so $R=2R_0$ , thus having:

$\frac{2R_0-R_0}{R_0}=\frac{R_0}{R_0}=1=c(T-T_0)$

For this T must be:

$1=cT-cT_0$

$T=\frac{1+cT_0}{c}$

which for our values means (with $T=20^{\circ}C=293^{\circ}K$ , remember to write temperature in S.I., and that for silver $c=0.0038^{\circ}K^{-1}$ ):

$T=\frac{1+(0.0038^{\circ}K^{-1})(293^{\circ}K)}{(0.0038^{\circ}K^{-1})}=556^{\circ}K=283^{\circ}C$

3 0

2 years ago

What is the definition of a "revolution"? user: which planet is closest to the sun?

asambeis [7]

The correct answer is A. Mercury

6 0

3 years ago

Read 2 more answers

A box sits on the back of a flatbed truck. If the coefficient of static friction between the box and the truck bed is μs = 0.400

slava [35]

Answer:

28,699m

Explanation:

The force to make the box move should be μs.N=μs.m.g=m.|a|

then,

|a|=μs.g

Being

μs coefficient of static friction,

N the force made by the truck on the box caused by the gravity force,

m the mass,

g the acceleration of gravity

and a the acceleration of the truck.

$x = v \times t + \frac{1}{2} \times a \times {t}^{2}$

as the truck is stopping, the acceleration is negative. then,

$x = v \times t - \frac{1}{2} \times |a| \times {t}^{2}$

$|a| = v \div t \\ t = v \div |a|$

$x = v \times (v \div |a| ) - \frac{1}{2} \times |a| \times {(v \div |a|)}^{2}$

$x = v \times (v \div μs.g ) - \frac{1}{2} \times |a| \times {(v \div μs.g)}^{2}$

$x = \frac{{v}^{2}}{μs \times g} - \frac{1}{2} \times \frac{{v}^{2}}{μs \times g} \\ x = \frac{1}{2} \times \frac{{v}^{2}}{μs \times g} \\ x = 0.5 \times \frac{{(15m/s) }^{2} }{0.4 \times 9.8m/ {s}^{2} } = 28.699m$

28,699m

7 0

3 years ago

In a domestic electric circuit (220.V),an electric kettle of 3kW power rating is operatedthat has a current rating of 4A. What r

kozerog [31]

Answer:

(i) It will take longer (75/22 times) the time to boil a given quantity of water compared to when the current is working at its rated capacity

(ii) The reasons are;

(1) For economy; most of the appliances in the home only require low power circuitry with thinner wire while a separate high power circuitry is created directly from the main supply for the high electric power rated appliances

(2) For safety; to prevent the over heating of the electric circuits when an high electric power appliance needs to be connected an high power electric power outlet has to be specified

Explanation:

(i) The power rating of the kettle = 3 kW

The voltage rating of the circuit, V = 220 V

The current rating, I = 4 A

The formula for electric power = I² × R = I × V

Therefore, we have;

Power produced = 220 V × 4 A = 880 V·A = 800 W

Hence, since the power produced is below the power rating of the electric kettle, it will take a longer time to boil a given amount of water than specified by the kettle manufacturer

The energy supplied H = V×I×t

Where:

t = Time in seconds

Therefore, we have;

3 kW = 3000 W;

3000 × t₁ = 880 × t₂

t₂/t₁ =3000/880 = 75/22

Hence the kettle will take 75/22 multiplied by the time it takes when working at rating capacity to boil a given quantity of water

(ii) This is so because the power consumption already factored in the electrical installation as well as the type of appliances utilized in the home allow for several low power rating consumption and few high power rating consumption

Therefore, for both economy and safety the electrical circuit are split to allow for the use of very thick copper or aluminium electric cables in the high power rating electric circuits to which can be plugged high electric power consuming devices such as the water heater and electric cooker

The low electric power consuming devices, such as the electric bulb and fans are connected to the low or "regular" power rating electric circuit outlets

The current required for high power and low power appliances is different and also the fuse rating required for both the appliances different, so two separate circuits are used for high power and low power appliances.

6 0

3 years ago

The electric charge on an atom is neutral because the number of protons is the same as the number of _____and each of their indi

tester [92]

The blank should be electrons, I think.

4 0

3 years ago