A sound wave with a wavelength of 3200 cm travels 7,712 meters in 16 seconds. What is the frequency of the wave?

Which device provides electrical energy to run an electric circuit

REY [17]

The correct answer is

C. The battery

The battery is a device that provides a potential difference in the circuit, and so an electromotive force (e.m.f.) which pushes the electrons in the circuit from the negative pole towards the positive pole of the battery, so they move through the circuit. Therefore, it provides electrical energy.

8 0

3 years ago

Read 2 more answers

The tallest Ferris wheel in the world is located in Singapore. Standing 42 stories high and holding as many as 780 passengers, t

kakasveta [241]

Answer:

The speed of the riders on the Singapore Flyer is approximately 0.262 m/s

Explanation:

The dimensions of the tallest Ferris wheel in the world are;

The diameter of the Ferris wheel, D = 150 m

The tine it takes the Ferris wheel to make a full circle, T = 30 minutes = 30 min × 60 s/min = 1,800 seconds

The angular velocity of the Ferris wheel, ω = 2·π/T

The linear velocity of the Ferris wheel, v = r·ω = The speed of the riders

Where;

r = The radius of the Ferris wheel = D/2

D = 150 m

∴ r = 150 m/2 = 75 m

∴ v = r·2·π/T

∴ v = 75 m × 2 × π/(1,800 s) ≈ 0.262 m/s

The speed of the riders on the Singapore Flyer, v ≈ 0.262 m/s

8 0

3 years ago

In the demonstration by Cal’s teacher, the string represents the force that keeps the planet in orbit. Which statement BEST desc

Flauer [41]

Answer:

yessyes

Explanation:

yes

5 0

2 years ago

A light source of wavelength λ illuminates a metal with a work function (a.k.a., binding energy) of BE=2.00 eV and ejects electr

slega [8]

<h2>Answer: 1.011 eV</h2>

Explanation:

The described situation is the photoelectric effect, which consists of the emission of electrons (electric current) that occurs when light falls on a metal surface under certain conditions.

If we consider the light as a stream of photons and each of them has energy, this energy is able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a <u>kinetic energy. </u>

This is what Einstein proposed:

Light behaves like a stream of particles called photons with an energy $E$ :

$E=h.f$ (1)

So, the energy $E$ of the incident photon must be equal to the sum of the Work function $\Phi$ of the metal and the kinetic energy $K$ of the photoelectron:

$E=\Phi+K$ (2)

Where $\Phi$ is the <u>minimum amount of energy required to induce the photoemission of electrons from the surface of a metal, and </u><u>its value depends on the metal. </u>

In this case $\Phi=2eV$ and $K_{1}=4eV$

So, for the first light source of wavelength $\lambda_{1}$ , and applying equation (2) we have:

$E_{1}=2eV+4eV$ (3)

$E_{1}=6eV$ (4)

Now, substituting (1) in (4):

$h.f=6eV$ (5)

Where:

$h=4.136(10)^{-15}eV.s$ is the Planck constant

$f$ is the frequency

Now, the <u>frequency has an inverse relation with the wavelength </u>

$\lambda_{1}$ :

$f=\frac{c}{\lambda_{1}}$ (6)

Where $c=3(10)^{8}m/s$ is the speed of light in vacuum

Substituting (6) in (5):

$\frac{hc}{\lambda_{1}}=6eV$ (7)

Then finding $\lambda_{1}$ :

$\lambda_{1}=\frac{hc}{6eV }$ (8)

$\lambda_{1}=\frac{(4.136(10)^{-15} eV.s)(3(10)^{8}m/s)}{6eV}$

We obtain the wavelength of the first light suorce $\lambda_{1}$ :

$\lambda_{1}=2.06(10)^{-7}m$ (9)

Now, we are told the second light source $\lambda_{2}$ has the double the wavelength of the first:

$\lambda_{2}=2\lambda_{1}=(2)(2.06(10)^{-7}m)$ (10)

Then: $\lambda_{2}=4.12(10)^{-7}m$ (11)

Knowing this value we can find $E_{2}$ :

$E_{2}=\frac{hc}{\lambda_{2}}$ (12)

$E_{2}=\frac{(4.136(10)^{-15} eV.s)(3(10)^{8}m/s)}{4.12(10)^{-7}m}$ (12)

$E_{2}=3.011eV$ (13)

Knowing the value of $E_{2}$ and $\lambda_{2}$ , and knowing we are working with the same work function, we can finally find the maximum kinetic energy $K_{2}$ for this wavelength: