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3 years ago

How many neutrons does element X have if its atomic number is 22 and its mass number is 96?

1 answer:

6 0

1. The mass number is protons + neutrons = mass number. In this case, we have protons + neutron = 164.The atomic number is simply the number of protons so we have 43 + neutrons = 164. Subtracting 43 from both sides we get neutrons = 121.
2. = 4

3. The number of protons in the nucleus does not equal the number of neutrons.

A=mass number:
Z=atomic number (= number of protons)
N=number of neutrons:

A=Z+N

If the number of protons in the nucleus is equal the number of neutrons , we would have an even mass number; because Z=N=x; then A=x+x=2x (this is always an even number) but 23 is an odd number, therefore the number of protons in the nucleus does not equal the number of neutrons.

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When is the electric flux on a section of a closed surface positive?.

rodikova [14]

When the electric field pierces outward through the section.

5 0

2 years ago

A turntable that spins at a constant 80.0 rpmrpm takes 3.50 ss to reach this angular speed after it is turned on. Find its angul

Veronika [31]

Answer:

The angular acceleration is <u>2.39 rad/s²</u>.

The number of degrees it rotates is <u>841.68 degrees</u>.

Explanation:

Given:

Initial angular speed (ω₀) = 0 rad/s

Final angular speed in rpm (N) = 80.0 rpm

Time taken (t) = 3.50 s

First, let us determine the final angular speed in radians per second.

We know that,

$\omega=\frac{2\pi N}{60}\ rad/s$

Plug in the values and find the final angular speed, 'ω'. This gives,

$\omega=\frac{2\pi\times 80.0}{60}=8.38\ rad/s$

Now, using equation of motion for rotational motion, we have:

$\omega=\omega_0+\alpha t\\\\\alpha\to angular\ acceleration$

Plug in the given values and solve for α. This gives,

$8.38=0+\alpha \times 3.50\\\\\alpha=\frac{8.38}{3.50}=2.39\ rad/s^2$

Therefore, the angular acceleration is 2.39 rad/s².

Now, again using rotational equation of motion relating angular displacement, we have:

$\omega^2=\omega_0^2+2\alpha\theta\\\\\theta=\frac{\omega^2-\omega_0^2}{2\alpha }$

Plug in the given values and solve for 'θ'. This gives,

$\theta=\frac{(8.38)^2-0}{2\times 2.39}\\\\\theta=\frac{70.2244}{4.78}=14.69\ rad$

Convert radians to degrees using the conversion factor. This gives,

π radians = 180°

So, 1 radian =( 180 ÷ π ) degrees

Therefore, $14.69\ rad=14.69\times (\frac{180}{\pi})=841.68^\circ$

So, the number of degrees it rotates is 841.68 degrees.

3 0

3 years ago

A low orbit satellite at 100 km altitude had a camera that resolved a car location to within 0.3 meter. Find the minimum diamete

NeX [460]

Answer:

Minimum diameter of the camera lens is 22.4 cm

The focal length of the camera's lens is 300cm

Explanation:

y = Resolve distance = 0.3 m

h = Height of satellite = 100 km

λ = Wavelength = 550 nm

Angular resolution

$tan\theta\approx \theta =\frac{y}{h}\\\Rightarrow \theta=\frac{0.3}{100\times 10^3}=3\times 10^{-6}$

From Rayleigh criteria

$sin\theta=1.22\frac{\lambda}{D}\\\Rightarrow D=1.22\frac{\lambda}{sin\theta}\\\Rightarrow D=1.22\frac{550\times 10^{-9}}{sin3\times 10^{-6}}=0.2236\ m=22.4\ cm$