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3 years ago

What are all stars made of

1 answer:

7 0

Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. Aside from our sun, the dots of light we see in the sky are all light-years from Earth. They are the building blocks of galaxies, of which there are billions in the universe. It’s impossible to know how many stars exist, but astronomers estimate that in our Milky Way galaxy alone, there are about 300 billion.

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Rarefaction occurs only in a _______ wave.

Olenka [21]

<u>Answers
</u>

1) B. longitudinal.

2) B. air is cooler than the ground.

<u>Explanation
</u>

There are two categories of a wave. That is transverse and longitudinal waves. Transverse waves forms crests and troughs while longitudinal forms compressions and rarefaction as they travel. Rarefactions are regions where the wavelengths are longer than other regions.

As the ray of light moves from an optically less dense to a more dense region it bends towards the normal.

If the sound is bending away from the earth's surface, then the ground must be warmer than the air. As the sound travels it moves from optically dense medium to a less dense medium. For this reason it bends away from the normal. This can only happen when, B. air is cooler than the ground.

4 0

3 years ago

Read 2 more answers

If low CVP precipitates a suction alarm, rapid infusion of volume can remedy the situation after dropping the P-level.

motikmotik

Answer:

Explanation:

8 0

3 years ago

Consider the data collected in science class. Different masses were thrown with varied amounts of

lesya [120]

Answer:

A: In all cases, the acceleration was the same.

Explanation:

I know this because its a clear obvious answer not only that it was one of my USA TESTPREP questions and it was right.

All you mainly have to do is the math - F=ma , In each case , the acceleration is 5 m/s squared

4 0

3 years ago

Read 2 more answers

How far back into the universe are we able to see? Explain.

Nadusha1986 [10]

Answer:

About 46 billion light years Because space expands so what we didn’t see before is what we could see now. An example could be how everyone thought Pluto was a regular sized planet but once you get a look at the bigger picture and compare it to other thing in space we now know Pluto is a dwarf planet.

3 0

3 years ago

An LC circuit is built with a 20 mH inductor and an 8.0 PF capacitor. The capacitor voltage has its maximum value of 25 V at t =

Margaret [11]

Answer:

a) the required time is 0.6283 μs

b) the inductor current is 0.5 mA

Explanation:

Given the data in the question;

The capacitor voltage has its maximum value of 25 V at t = 0

i.e V $_m$ = V₀ = 25 V

we determine the angular velocity;

ω = 1 / √( LC )

ω = 1 / √( ( 20 × 10⁻³ H ) × ( 8.0 × 10⁻¹² F) )

ω = 1 / √( 1.6 × 10⁻¹³ )

ω = 1 / 0.0000004

ω = 2.5 × 10⁶ s⁻¹

a) How much time does it take until the capacitor is fully discharged for the first time?

V $_m$ = V₀sin( ωt )

we substitute

25V = 25V × sin( 2.5 × 10⁶ s⁻¹ × t )

divide both sides by 25 V

sin( 2.5 × 10⁶ × t ) = 1

( 2.5 × 10⁶ × t ) = π/2

t = 1.570796 / (2.5 × 10⁶)

t = 0.6283 × 10⁻⁶ s

t = 0.6283 μs

Therefore, the required time is 0.6283 μs

b) What is the inductor current at that time?

$I$ (t) = V₀√(C/L) sin(ωt)

{ sin(ωt) = 1 )

$I$ (t) = V₀√(C/L)

we substitute

$I$ (t) = 25V × √( ( 8.0 × 10⁻¹² F ) / ( 20 × 10⁻³ H ) )

$I$ (t) = 25 × 0.00002

$I$ (t) = 0.0005 A

$I$ (t) = 0.5 mA

Therefore, the inductor current is 0.5 mA

8 0

3 years ago