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vazorg [7]
1 year ago
15

the half-life of iodine-131 is 8.1 days. how much time had passed if i only have one-fourth of the original sample?​

Physics
1 answer:
morpeh [17]1 year ago
8 0

Answer:

16.2 days

Explanation:

Find the number of halflives:

1/2   *  1/2 =  1/4     so <u>two</u>   halflives have passed

   2 * 8.1 days = 16.2 days

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If the temperature of a volume of ideal gas increases for 100°C to 200°C, what happens to the average kinetic energy of the mole
mina [271]

Answer:\Delta E=2.0715\times 10^{-21} J

Explanation:

Given

Temperature of the gas is increased from 100 to 200

Also we know that average kinetic energy of the molecules is

E=\frac{3}{2}\cdot \frac{R}{N_A}T

Where

R=Gas constant

N_A=Avogadro's number

T=Temperature in kelvin

\frac{R}{N_A}=1.381\times 10^{-23}

So kinetic energy increases by

\Delta E=\frac{3}{2}\times 1.381\times 10^{-23}\left ( 200-100\right )

\Delta E=2.0715\times 10^{-21} J

8 0
3 years ago
Monochromatic light from a point source is directed toward the sharp edge of a solid object. How does diffraction change the ima
Anna71 [15]

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6 0
3 years ago
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Imagine an alternate universe where all of the quantum number rules were identical to ours except m_{s} had three allowed values
marishachu [46]

Answer:

so in a given orbital there can be 3 electrons.

Explanation:

The Pauli exclusion principle states that all the quantum numbers of an electron cannot be equal, if the spatial part of the wave function is the same, the spin part of the wave function determines how many electrons fit in each orbital.

In the case of having two values, two electrons change. In the case of three allowed values, one electron fits for each value, so in a given orbital there can be 3 electrons.

5 0
3 years ago
A horizontal 810-N merry-go-round of radius 1.60 m is started from rest by a constant horizontal force of 55 N applied tangentia
Sloan [31]

Answer:

576 joules

Explanation:

From the question we are given the following:

weight = 810 N

radius (r) = 1.6 m

horizontal force (F) = 55 N

time (t) = 4 s

acceleration due to gravity (g) = 9.8 m/s^{2}

K.E = 0.5 x MI x ω^{2}

where MI is the moment of inertia and ω is the angular velocity

MI = 0.5 x m x r^2

mass = weight ÷ g = 810 ÷ 9.8 = 82.65 kg

MI = 0.5 x 82.65 x 1.6^{2}

MI = 105.8 kg.m^{2}

angular velocity (ω) = a x t

angular acceleration (a) = torque ÷ MI

where torque = F x r = 55 x 1.6 = 88 N.m

a= 88 ÷ 105.8 = 0.83 rad /s^{2}

therefore

angular velocity (ω) = a x t = 0.83 x 4 = 3.33 rad/s

K.E = 0.5 x MI x ω^{2}

K.E = 0.5 x 105.8 x 3.33^{2} = 576 joules

6 0
3 years ago
Which planetery body has the greast gravitational pull?
Nataly [62]
Answer should be the earth
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2 years ago
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