What is an atom really need help

Basile [38]

Answer:

T = 0.01 s

Explanation:

Given that,

The frequency of the beats of a hummingbird, f = 100 Hz

We need to find the period of the hummingbirds flaps. Let the time is t. We know that the relation between frequency and time period is given by :

T = 1/f

Put all the values,

T = 1/100 = 0.01 s

So, the time period of the humming bird is 0.01 s.

3 0

3 years ago

You have a great summer job working in a cancer research laboratory. Your team is trying to construct a gas laser that will give

Alchen [17]

Answer:

ΔE = 7.559 eV , λ = 1,645 10⁻⁷ m

Explanation:

For this exercise we can use the Bohr model for ionized atom with only one free electron,

r_n = n² a₀ / Z

E_n = -13,606 Z² / n²

Where a₀ is the Bohr radius of the hydrogen atom (a₀ = 0.0529 nm), Z is the atomic number of the atom under study and 13.606 eV is the energy of the ground state of Hydrogen.

In our case the Helium atom has two protons Z = 2

let's calculate the quantum number and the energy of each orbit

r_n = 0.30 nm

n₁ = √ (r_n Z / a₀)

n₁ = √ (0.30 2 / 0.0529)

Note that we do not have to reduce the radius since they are all in nanometers

n₁ = 3.3

since n is an integer we approximate it to

n₁ = 3

r_n = 0.20 nm

n₂ = √ (0.2 2 / 0.0529)

n₂ = 2.7

To approximate this value we must assume that there could be some error in the medicinal radio,

n₂ = 2

having the quantum numbers of the two radius we can calculate their energy

E₃ = - 13,606 2²/3²

E₃ = - 6.047 eV

E₂ = -13.606 2²/2²

E₂ = -13.606 eV

the energy of the emitted photon is

ΔE = E₃ - E₂

ΔE = -6.047 + 13.606

ΔE = 7.559 eV

You do not indicate in the exercise if you want the energy or the wavelength of the photon,

to find the wavelength We use the Planck relation

E = h f

c = λ f

E = h c /λ

λ = h c / E

we must reduce the energy to the SI system

E = 7.559 ev (1.6 10⁻¹⁹ J / 1eV) = 12.09 10⁻¹⁹ J

λ = 6.63 10⁻³⁴ 3 10⁸ / 12.09 10⁻¹⁹

λ = 1,645 10⁻⁷ m

6 0

4 years ago

a block is pushed up a frictionless 40 incline. if the initial velocity after the push is 5.00 m/s. how far along the incline do

Lana71 [14]

Answer:

d=1.982m, t=1.019s

Explanation:

There are different approaches we can take to solve this problem. You could either solve this by using conservation of energy or by taking a kinematic approach. I'll solve this by using kinematics. So, the very first thing we need to do in order to solve this is do a drawing of the situation so we can analyze it better. (See attached picture).

So, since we are talking about an inclined plane, we can see that the force of gravity is being split into an x and y components if we incline the axis of coordinates. Taking this into account we can see that:

$\sum F_{x}=ma_{x}$

Since there is no friction in our system, then the only force acting upon the box is the force of gravity, or weight. Since we are taking the upwards direction as the positive direction of movement, we can say that the force of gravity is excerting a negative influence on our box, so this acceleration will be negative, so our sum of forces will now look like this:

$-mg sin(40^{o})=ma$

we can cancel the masses out so we can see that:

a=-g sin(40°)

$a=-9.81m/s^{2} sin(40^{o})$

We have now enough information to solve our problem.

we can take the following equation to find the distance the block travels up the incline:

$x=\frac{V_{f}^{2}-V_{0}^{2}}{2a}$

we know the final velocity must be zero, so we can use the provided data to solve our formula:

$x=\frac{(0)^{2}-(5m/s)^{2}}{2(-9.81m/s^{2})sin 40^{o}}$

which yields:

x=1.982m

In order to find the time it takes for the block to return to its original position we can use the following formula:

$x=V_{0}t+\frac{1}{2}at^{2}$

since x=0 is the starting point we can use that to solve our equation:

$0=5t+\frac{1}{2}(-9.81sin 40^{o})t^{2}$

which simplifies to:

$0=5t-4.905t^{2}$

which can now be solved for t

t(5-4.905t)=0

t=0 and 5-4.905t=0

t=0 and $t=\frac{5}{4.905}=1.019$

so the time it takes the block to return to its original position is

t= 1.019s

6 0

3 years ago

At t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is 6.00 i + 4.00 j m/s2 . It moves at constan

Jet001 [13]

The particle moves with constant speed in a circular path, so its acceleration vector always points toward the circle's center.

At time $t_1$ , the acceleration vector has direction $\theta_1$ such that

$\tan\theta_1=\dfrac{4.00}{6.00}\implies\theta_1=33.7^\circ$

which indicates the particle is situated at a point on the lower left half of the circle, while at time $t_2$ the acceleration has direction $\theta_2$ such that

$\tan\theta_2=\dfrac{-6.00}{4.00}\implies\theta_2=-56.3^\circ$

which indicates the particle lies on the upper left half of the circle.

Notice that $\theta_1-\theta_2=90^\circ$ . That is, the measure of the major arc between the particle's positions at $t_1$ and $t_2$ is 270 degrees, which means that $t_2-t_1$ is the time it takes for the particle to traverse 3/4 of the circular path, or 3/4 its period.

Recall that

$\|\vec a_{\rm rad}\|=\dfrac{4\pi^2R}{T^2}$

where $R$ is the radius of the circle and $T$ is the period. We have

$t_2-t_1=(5.00-2.00)\,\mathrm s=3.00\,\mathrm s\implies T=\dfrac{3.00\,\rm s}{\frac34}=4.00\,\mathrm s$

and the magnitude of the particle's acceleration toward the center of the circle is

$\|\vec a_{\rm rad}\|=\sqrt{\left(6.00\dfrac{\rm m}{\mathrm s^2}\right)^2+\left(4.00\dfrac{\rm m}{\mathrm s^2}\right)^2}=7.21\dfrac{\rm m}{\mathrm s^2}$

So we find that the path has a radius $R$ of

$7.21\dfrac{\rm m}{\mathrm s^2}=\dfrac{4\pi^2R}{(4.00\,\mathrm s)^2}\implies\boxed{R=2.92\,\mathrm m}$

8 0

3 years ago

. What happens to the polarity of an electromagnet when the direction of the current passing through it is reversed?

eduard

Answer:

The polarity of electromagnet also gets reversed when the direction of current is reversed. The current flows from negative terminal to positive terminal in an electromagnet due to the flow of electrons so polarity is also established in the electromagnet. As, the current direction is reversed, the polarity of magnet also gets reversed because the polarity of magnet depends on the direction of the current.

6 0

4 years ago