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4 years ago

Jack tries to place magnets on his refrigerator at home, but they won’t stick. What could be the reason?

1 answer:

5 0

The most probable reason why the magnets won't stick on the refrigerator is that the body of the refrigerator and the magnets have like poles. If both have negative or both have positive poles facing each other, they will repel. In principle, magnets are attracted to opposite poles and like poles repel.

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In each of the parts of this question, a nucleus undergoes a nuclear decay. Determine the resulting nucleus in each case.

MA_775_DIABLO [31]

A) Francium-223

In an alpha decay, a nucleus decay emitting an alpha particle, which corresponds to a nucleus of helium: so, it consists of 2 protons and 2 neutrons.

$X \rightarrow X' + \alpha$

This means that in the decay:

- The original nucleus loses 2 protons --> so its atomic number Z decreases by 2 units

- The original nucleus loses 2 nucleons (2 protons and 2 neutrons) --> so its mass number A decreases by 4 units

In this example, the original nucleus is Ac (Actinium), with

Z = 89

A = 227

After the decay, it must be

Z - 2 = 89 - 2 = 87

A - 4 = 227 - 4 = 223

We see from the periodict table, Z=87 corresponds to Francium (Fr), so the final nucleus will be francium-223 (the isotope of francium with 223 nucleons).

B) Polonium-211

In a beta-minus decay, a neutron in the nucleus turns into a proton, emitting a fast-moving electron (the beta particle) and an anti-neutrino.

$n \rightarrow p + e^- + \bar{\nu}$

Therefore, in this process:

- The original nucleus gains 1 protons, so its atomic number Z increases by 1 unit

- The original nucleus does not lose/gain nucleons, so its mass number A remains the same

In this example, the original nucleus is Bi (bismuth)-211, with

Z = 83

A = 211

So After the decay, it will be

Z + 1 = 83 + 1 = 84

A = 211

So, the nucleus will be Polonium (Z=84), isotope with 211 nucleons.

C) Neon-22

In a beta-plus decay, a proton in the nucleus turns into a neutron, emitting a fast-moving positron (the beta particle) and a neutrino.

$p \rightarrow n + e^+ +\nu$

Therefore, in this process:

- The original nucleus loses 1 protons, so its atomic number Z decreases by 1 unit

- The original nucleus does not lose/gain nucleons, so its mass number A remains the same

In this example, the original nucleus is Na (sodium)-22, with

Z = 11

A = 22

So After the decay, it will be

Z - 1 = 11 - 1 = 10

A = 22

So, the nucleus will be Neon (Z=10), isotope with 22 nucleons.

D) Technetium-98

In a gamma decay, an unstable nucleus emits a gamma ray:

$X' \rightarrow X + \gamma$

In this process, only energy is released (in the form of gamma ray), so there is no gain/loss of protons/neutrons in the process. This means that:

- The atomic number Z remains constant

- The mass number A remains constant

In this example, we have a nucleus of Tc (Technetium)-98, with

Z = 43

A = 98

These numbers will not change during the decay: this means that after the decay, we will still have a nucleus of Technetium-98.

8 0

3 years ago

What layer forms the largest portion of Earth

lorasvet [3.4K]

The earth is made up of 3 layers,the crust,mantle,and core,but the largest is the mantle

8 0

3 years ago

Read 2 more answers

a crane convert 1000oule of energy in one second if it can do any work in one minute calculate the work done

dedylja [7]

A 1000J or 1kJ of energy in 1 second implies that in 1 minute there will be 60kJ of energy converted.

Work is the defined as energy consumed thought time.

$W=\dfrac{E}{t}$

In our case,

$W=\dfrac{60\mathrm{kJ}}{60\mathrm{s}}=1\cdot10^3\dfrac{\mathrm{J}}{\mathrm{s}}=\boxed{10^3\mathrm{W}}$

Hope this helps!

8 0

4 years ago

As a consequence of Republicans’ highly irresponsible game of chicken with the debt ceiling, it’s looking increasingly like Demo

Alexxx [7]

HELP ME PLEASE

Silently he crept through jagged thornbushes. Bare feet moved swiftly over hot, arid soil to the edge of a waterhole where the kudu was drinking. The great animal suddenly looked up, spiral horns curving sharply into the endless African sky. Nsue did not reach for his pouch of poisoned arrows. He had no heart for killing. This would not be the day he would change his childish boyhood name.

How does paragraph 1 contribute to Nsue’s development?

It establishes Nsue’s disappointment at not finding a suitable animal to bring to the feast.

It establishes Nsue’s apprehension of participating in the Festival of the New Moon.

It establishes Nsue’s desire to become a great storyteller like Gao, the Old One.

It establishes Nsue’s motivation to find something to take to the feast.

7 0

3 years ago

A certain sound contains the following frequencies: 400 Hz, 1600 Hz, and 2400 Hz. Select the best description of this sound View

julsineya [31]

Answer:

Explanation:

The 3 frequencies found in the sound waveform (400, 1600, and 2400 Hz are related between them, being 400 Hz the fundamental frequency of the sound, and 1600 Hz and 2400 Hz, harmonics (overtones of the fundamental) according to this relationship:

1600 Hz = 4* 400 Hz (4th Harmonic)

2400 Hz = 6* 400 Hz (6th Harmonic)

3 0

4 years ago