What effect does the Boat Velocity have on the waves seen by the observer?

Radon-222 ( 222/86 Rn) is a radioactive gas with a half-life of 3.82 days. A gas sample contains 4.1 e 8 radon atoms initially.

kow [346]

Answer :

(a) The number of radon atoms will remain after 12 days is, $4.67\times 10^7$

(b) The number of radon nuclei have decayed by this time will be, $3.6\times 10^8$

Explanation :

For part (a) :

Half-life = 3.82 days

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{3.82\text{ days}}$

$k=1.81\times 10^{-1}\text{ days}^{-1}$

Now we have to calculate the number of radon atoms will remain after 12 days.

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $1.81\times 10^{-1}\text{ days}^{-1}$

t = time passed by the sample = 12 days

a = initially number of radon atoms = $4.1\times 10^8$

a - x = number of radon atoms left = ?

Now put all the given values in above equation, we get

$12=\frac{2.303}{1.81\times 10^{-1}}\log\frac{4.1\times 10^8}{a-x}$

$a-x=4.67\times 10^7$

Thus, the number of radon atoms will remain after 12 days is, $4.67\times 10^7$

For part (b) :

Now we have to calculate the number of radon nuclei will have decayed by this time.

The number of radon nuclei have decayed = Initial number of radon atoms - Number of radon atoms left

The number of radon nuclei have decayed = $(4.1\times 10^8)-(4.67\times 10^7)$

The number of radon nuclei have decayed = $3.6\times 10^8$

Thus, the number of radon nuclei have decayed by this time will be, $3.6\times 10^8$

5 0

3 years ago

Magnetic fields are produced either by electric currents or time-varying electric fields.

Fynjy0 [20]

Answer:

option (a)

Explanation:

The magnetic field is produced by the electric current, and the direction of magnetic field is given by the Maxwells' right hand rule.

The magnetic field is also be produced by the time varying magnetic fields.

6 0

3 years ago

What is the difference between newtons law of gravitation and Coulombs law?

svlad2 [7]

Coulomb's law explains the force between the charges whereas Newton's law of gravitation explains the force between the masses. ... The electrostatic force may be positive or negative in the case of Coulomb's law but the force is always negative in the case of Newton's law of gravitation

4 0

3 years ago

How dose the momentum of a car moving at 25 m/s compare to the exact same car moving at 50 m/s

Vesnalui [34]

They both have momentum but the car traveling at 50 m/s has more momentum because of the speed difference

8 0

4 years ago

The surface area of the earth's crust is 5.10*10^8km^2. The average thickness of the earth's crust is 35km. The mean density of

Mars2501 [29]

Answer:

The answer is $V = 1.785 \times 10^{10}\ Km^3$ .

Explanation:

You are asking only for the total volume, so the important data here is the surface area of the earth's crust,

$A = 5.10 \times 10^8\ Km^2$

and the average thickness of the earth's crust,

$h = 35\ Km$ .

Imagine that you can stretch the surface area as if it were a blanket, now if you want to calculate its volume, you just need to multiply its area by its thickness,

$V = A*h = 1.785 \times 10^{10}\ Km^3$ .

4 0

3 years ago