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3 years ago

When an atom is neutral the...?

Physics

2 answers:

KATRIN_1 [288]3 years ago

5 0

Answer:

Explanation:

if numbers of protons and electrons are equal, the atom is neutral

marin [14]3 years ago

4 0

Answer:

C.the number of protons and electrons are the same.

Explanation:

Protons have a positive charge, while electrons have a negative charge.

So, if there are more electrons (-) than protons (+), the atom will have a negative charge.

If the atom has more protons (+) than electrons (-), it will have a positive charge.

If they have the same number of negative and positive, they "cancel" out, making it neutral.

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Calculate the energy transfers in joules by a 4kW by appliances left for 2 minutes

Marianna [84]

Answer: 480 kJ

Explanation: Energy = power · time

E = Pt = 4000 W · 120 s = 480 000 J

5 0

3 years ago

A 26-cm-long wire with a linear density of 20 g/m passes across the open end of an 86-cm-long open-closed tube of air. If the wi

damaskus [11]

Answer: T = 472.71 N

Explanation: The wire vibrates thus making sound waves in the tube.

The frequency of sound wave on the string equals frequency of sound wave in the tube.

L= Length of wire = 26cm = 0.26m

u=linear density of wire = 20g/m = 0.02kg/m

Length of open close tube = 86cm = 0.86m

Sound waves in the tube are generated at the second vibrational mode, hence the relationship between the length of air and and wavelength is given as

L = 3λ/4

0.86 = 3λ/4

3λ = 4 * 0.86

3λ = 3.44

λ = 3.44/3 = 1.15m.

Speed of sound in the tube = 340 m/s

Hence to get frequency of sound, we use the formulae below.

v = fλ

340 = f * 1.15

f = 340/ 1.15

f = 295.65Hz.

f = 295.65 = frequency of sound wave in pipe = frequency of sound wave in string.

The string vibrated at it fundamental frequency hence the relationship the length of string and wavelength is given as

L = λ/2

0.26 = λ/2

λ = 0.52m

The speed of sound in string is given as v = fλ

Where λ = 0.52m f = 295.65 Hz

v = 295.65 * 0.52

v = 153.738 m/s.

The velocity of sound in the string is related to tension, linear density and tension is given below as

v = √(T/u)

153.738 = √T/ 0.02

By squaring both sides

153.738² = T / 0.02

T = 153.738² * 0.02

T = 23,635.372 * 0.02

T= 472.71 N

3 0

3 years ago

A long, thin solenoid has 390 turns per meter and a radius of 1.20 cm. The current in the solenoid is increasing at a uniform ra

gtnhenbr [62]

To solve this problem it is necessary to apply the concepts related to Faraday's law and the induced emf.

By definition the induced electromotive force is defined as

$\int E dl = -\frac{d\phi}{dt}$

$\int E dl = -(\frac{dB}{dt})A$

Where,

$\phi =$ Electric field

B = Magnetic Field

A = Area

At the theory the magnetic field is defined as,

$B = \mu_0 NI$

Where,

N = Number of loops

I = current

$\mu_0 =$ Permeability constant

We know also that the cross sectional area, is the area from a circle, and the length is equal to the perimeter then

A = \pi r^2

l = 2\pi r

Replacing at the previous equation we have that

$E (2\pi r) = \mu_0 n (\frac{di}{dt})(\pi R^2)$

Where,

R = Radius of the solenoid

r = The distance from the axis

Re-arrange to find the current in function of time,

$\frac{di}{dt} = \frac{Er}{\mu_0 NR^2}$

Replacing our values we have

$\frac{di}{dt} = \frac{(8.00*10^{-6})(0.0348)}{(4\pi*10^{-7})(390)(1.2*10^-2)^2}$

$\frac{di}{dt} = 3.94487A/s$

8 0

3 years ago

The average human hair has a diameter of 100,000 nm. We can see individual hairs because hair has a diameter greater than the wa

sertanlavr [38]

B is the correct answer, since all others are not true or are based on assumption

6 0

3 years ago

What does the text mean when it says “naming an elements is like creating history

dolphi86 [110]

Answer: When you name an element, it's usually because the element is newly discovered. So by naming an element you are creating something that will last throughout history.

Explanation:

5 0

3 years ago