All categories

4 years ago

Who is Janna Levin:

Physics

1 answer:

viva [34]4 years ago

8 0

Answer:

Janna levin is a cosmologist and professor at physics.

She is an american by race

She was the presenter of Nova feature Black hole Apocalypse and has writtenany science non-fiction books

www.jannalevin.com is her own page where u get her correct info and bio

You might be interested in

Use this technique to find a formula for the intensity I of a sound, in terms of the sound level β and the reference intensity I

denis23 [38]

Answer:

$I = I_o (10^{\frac{\beta}{10}})$

Explanation:

As we know that sound level is given as

$\beta = 10 Log (\frac{I}{I_o})$

so here we have

$\frac{\beta}{10} = Log(\frac{I}{I_o})$

now we can take anti log both sides

$10^{\frac{\beta}{10}} = \frac{I}{I_o}$

so we have

$I = I_o (10^{\frac{\beta}{10}})$

so above is the expression for the intensity of sound in terms of reference intensity and sound level

4 0

3 years ago

A spherical wave with a wavelength of 2.0 mm is emitted from the origin. At one instant of time, the phase at rrr = 4.0 mm is πr

max2010maxim [7]

Complete Question

A spherical wave with a wavelength of 2.0 mm is emitted from the origin. At one instant of time, the phase at r_1 = 4.0 mm is π rad. At that instant, what is the phase at r_2 = 3.5 mm ? Express your answer to two significant figures and include the appropriate units.

Answer:

The phase at the second point is $\phi _2 = 1.57 \ rad$

Explanation:

From the question we are told that

The wavelength of the spherical wave is $\lambda = 2.0 \ mm = \frac{2}{1000} = 0.002 \ m$

The first radius is $r_1 = 4.0 \ mm = \frac{4}{1000} = 0.004 \ m$

The phase at that instant is $\phi _1 = \pi \ rad$

The second radius is $r_2 = 3.5 \ mm = \frac{3.5}{1000} = 0.0035 \ m$

Generally the phase difference is mathematically represented as

$\Delta \phi = \phi _2 - \phi _1$

this can also be expressed as

$\Delta \phi = \frac{2 \pi }{\lambda } (r_2 - r_1 )$

So we have that

$\phi _2 - \phi _1 = \frac{2 \pi }{\lambda } (r_2 - r_1 )$

substituting values

$\phi _2 - \pi = \frac{2 \pi }{0.002 } ( 0.0035 - 0.004 )$

$\phi _2 = \frac{2 \pi }{0.002 } ( 0.0035 - 0.004 ) + 3.142$

$\phi _2 = 1.57 \ rad$

7 0

3 years ago

Which are responsible for holding atoms together?

Scrat [10]

Hey there!

Your answer: shared electrons

There would usually be two forces that would make an atom stick together. It would be the positive, and negative of a electric charge. All this coming together would be the electromagnetic force. This is liked we talked about, both positive and negative charges attracted. And that would be the strong force. Which then gives our answer to be electrons.

Your answer: shared electrons

4 0

3 years ago

Read 2 more answers

A magnetic field would be produced by a beam of

kumpel [21]

3 protons should be your answer

4 0

3 years ago

Roaring of a lion is different from the sound of the mosquito why?

Soloha48 [4]

Answer: