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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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A maser is a laser-type device that produces electromagnetic waves with frequencies in the microwave and radio-wave bands of the

rusak2 [61]

Answers:

a) $T=7.04(10)^{-10} s$

b) $5.11(10)^{12} cycles$

c) $2.06(10)^{26} cycles$

d) 46000 s

Explanation:

<h2>a) Time for one cycle of the radio wave</h2>

We know the maser radiowave has a frequency $f$ of $1,420,405,751.786 cycles/s$

In addition we know there is an inverse relation between frequency and time $T$ :

$f=\frac{1}{T}$ (1)

Isolating $T$ : $T=\frac{1}{f}$ (2)

$T=\frac{1}{1,420,405,751.786 cycles/s}$ (3)

$T=7.04(10)^{-10} s$ (4) This is the time for 1 cycle

<h2>b) Cycles that occur in 1 h</h2>

If $1h=3600s$ and we already know the amount of cycles per second $1,420,405,751.786 cycles/s$ , then:

$1,420,405,751.786 \frac{cycles}{s}(3600s)=5.11(10)^{12} cycles$ This is the number of cycles in an hour

<h2>c) How many cycles would have occurred during the age of the earth, which is estimated to be $4.6(10)^{9} years$ ?</h2>

Firstly, we have to convert this from years to seconds:

$4.6(10)^{9} years \frac{365 days}{1 year} \frac{24 h}{1 day} \frac{3600 s}{1 h}=1.45(10)^{17} s$

Now we have to multiply this value for the frequency of the maser radiowave:

$1,420,405,751.786 cycles/s (1.45(10)^{17} s)=2.06(10)^{26} cycles$ This is the number of cycles in the age of the Earth

<h2>d) By how many seconds would a hydrogen maser clock be off after a time interval equal to the age of the earth?</h2>

If we have 1 second out for every 100,000 years, then:

$4.6(10)^{9} years \frac{1 s}{100,000 years}=46000 s$

This means the maser would be 46000 s off after a time interval equal to the age of the earth

7 0

3 years ago

A town requiring 2.0 m3/s of drinking water has two sources, a local well with 15 g/m3 nitrate (as N) and a distant reservoir wi

kati45 [8]

Explanation:

Drinking water requirement in town 2.0 m^3/s of water per second

nitrate in local well nitrate per 15 $\mathrm{m}^{3}$ of water

nitrate in distant reservoir $=5 \mathrm{~g} / \mathrm{m}^{3}$

Let the flow rate of well

flow rate of reservoir $=y m^{3} / s$

Drinking water requirement is $45 \mathrm{ppm}$ or $45 \mathrm{~g} / \mathrm{m}^{3}$

therefore, the total flow of drinking water

8 0

2 years ago

The graph illustrates the activity level of three common digestive enzymes, across a range of pH values. Which enzyme is likely

vaieri [72.5K]

Answer:

(A) Pepsin

Explanation:

From the graph it is clear that pepsin is the only enzyme which works in highly acidic condintion in the digestive system.

less than 7 the liquid is acidic
above 7 the liquid is basic
at 7 the liquid is neutral

It has an optimum pH of about 1.5 at which its activity level is 8.5 as shown in graph.

7 0

3 years ago

Does plants have prokaryotic cells?

vova2212 [387]

No they have eukaryotic cells

7 0

3 years ago

Read 2 more answers

A crane lifts an air conditioner to the top of a building. If the building is 12 m high, and the air conditioner has a mass of 2

andrey2020 [161]

Work needed = 23,520 J

<h3>Further explanation</h3>

Given

height = 12 m

mass = 200 kg

Required

work needed by the crane

Solution

Work is the transfer of energy caused by the force acting on a moving object

Work is the product of force with the displacement of objects.

Can be formulated

W = F x d

W = Work, J, Nm

F = Force, N

d = distance, m

F = m x g

Input the value :

W = mgd

W = 200 kg x 9.8 m/s²x12 m

W = 23520 J

5 0

3 years ago