Which is the smallest atom? A. Magnesium (Mg) B. Calcium (Ca) C. Barium (Ba) D. Strontium (Sr)

The voltage across the diode indicates the energy given to charge carriers (electrons and holes, but more about that later in th

Elis [28]

Answer:

the charge carriers have an energy 2.8 10⁻¹⁹ J

Explanation:

The energy in a diode is conserved so the energy supplied must be equal to the energy emitted in the form of photons.

The energy of a photon is given by the Planck expression

E = h f

the speed of light, wavelength and frequency are related

c = λ f

we substitute

E = $\frac{h \ c}{\lambda}$

a red photon has a wavelength of lam = 700 nm = 700 10⁻⁹ m

we calculate the energy

E = 6.626 10⁻³⁴ 3 10⁸/700 10⁻⁹

E = 2.8397 10⁻¹⁹J

therefore the charge carriers have an energy 2.8 10⁻¹⁹ J,

3 0

3 years ago

Which of these best describes heat transfer through conduction? A) Heat transfer as electrons are excited in atoms. B) Heat tran

Setler79 [48]

I'd go for D here. It also fits in with the idea of thermal expansion - as something is heated up, molecules vibrate and maybe collide. they vibrate with bigger amplitudes, so taking up more space, so expanding. maybe

7 0

3 years ago

Read 2 more answers

When it comes to how ray lines are drawn, what makes the convex lens and concave mirror similar to each other?

Advocard [28]

Answer:

Convex lens and convex mirrors are similar that

1. They have the same image characteristics at various object positions

2. They possess a positive focal length

3. Both their ray lines converge to a particular focal point

4 0

3 years ago

An emf of 28.0 mV is induced in a 501 turn coil when the current is changing at a rate of 12.0 A/s. What is the magnetic flux th

dmitriy555 [2]

Answer:

Φ = 5.589×10⁻⁵ Wb

Explanation:

The inductance of a coil is given as

L = e/(di/dt) ..................... Equation 1

Where L = inductance of the coil, e = induced e.m.f, di/dt = rate of change of current in the coil.

Also,

The inductance of each turn of the coil when a magnetic field is step up in the coil is

L = NΦ/i ................. Equation 2

Where N = number of turns, Φ = magnetic field, i = current.

equating equation 1 and equation 2

e/(di/dt) = NΦ/i

making Φ the subject of the equation,

Φ = (e×i)/N.(di/dt) .................. Equation 3

Given: e = 28.0 mV = 0.028 V, N = 501 turns, di/dt = 12.0 A/s, i = 4.00 a

Substitute into equation 3,

Φ = (0.028×4)/(12×501)

Φ = 0.112/2004

Φ = 5.589×10⁻⁵ Weber

Φ = 5.589×10⁻⁵ Wb

6 0

3 years ago

Which of the following are thought to be rapidly rotating neutron stars with intense magnetic fields? Choose one answer.a. pulsa

frutty [35]

<h2>Answer: Pulsars</h2>

A <u>pulsar</u> is a neutron star that emits very intense electromagnetic radiation at short and periodic intervals ( rotating really fast) due to its intense magnetic field that induces this emission.

Nevertheless, it is important to note that all pulsars are neutron stars, but not all neutron stars are pulsars.

Let's clarify:

A neutron star, is the name given to the remains of a supernova. In itself it is the result of the gravitational collapse of a massive supergiant star after exhausting the fuel in its core.

Neutron stars have a small size for their very high density and they rotate at a huge speed.

However, the way to know that a pulsar is a neutron star is because of its high rotating speed.

8 0

3 years ago