All categories

2 years ago

If we start with 48 g of a radioactive substance with a 2 hour 12 life, how much is left after two half-lives?

Physics

1 answer:

ivolga24 [154]2 years ago

4 0

Explanation:

Half-life is the time taken for a radioactive material to decay to half its original composition:

Original mass = 48g

Half- life = 2hr

After four half lives;

Initially: 48g

First halving 24

Second halving 12

Third halving 6

Fourth halving 3

After second half life, we would have 12g

At fourth halving, we would have 3g

You might be interested in

Using 0.500 g of nichrome, you are asked to fabricate a wire with uniform cross-section. The resistance of the wire is 0.673 Ω.

mojhsa [17]

Explanation:

Given that,

Mass of Nichrome, m = 0.5 g

The resistance of the wire, R = 0.673 ohms

Resistivity of the nichrome wire, $\rho=10^{-6}\ \Omega -m$

Density, $d=8.31\times 10^3\ kg/m^3$

(A) The length of the wire is given by using the definition of resistance as :

Volume,

$V=A\times l\\\\A=\dfrac{V}{l}\\\\Since, V=\dfrac{m}{d}\\\\V=\dfrac{m}{d}\\\\V=\dfrac{0.5\times 10^{-3}}{8.31\times 10^3}\\\\V=6.01\times 10^{-8}\ m^3$

Area,

$A=\dfrac{V}{l}\\\\A=\dfrac{6.01\times 10^{-8}}{l}$ ....(1)

$R=\rho \dfrac{l}{A}\\\\l=\dfrac{RA}{\rho}\\\\l=\dfrac{0.673\times 6.01\times 10^{-8}}{l\times 10^{-6}}\\\\l=0.201\ m$

(b) Equation (1) becomes :

$A=\dfrac{6.01\times 10^{-8}}{l}\\\\A=\dfrac{6.01\times 10^{-8}}{0.201}\\\\\pi r^2=3\times 10^{-7}\\\\r=\sqrt{\dfrac{3\times 10^{-7}}{\pi}} \\\\r=3.09\times 10^{-4}\ m$

Hence, this is the required solution.

5 0

3 years ago

A sled of mass m is being pulled horizontally by a constant horizontal force of magnitude F. The coefficient of kinetic friction

steposvetlana [31]

Answer:

The average velocity of the sled is vavg = s/t.

Explanation:

Hi there!

The average velocity is calculated as the traveled distance over time:

vavg = Δx/Δt

Where:

vavg = average velocity.

Δx = traveled distance.

Δt = elapsed time.

We already know the traveled distance (s) and also know the time it takes the sled to travel that distance (t). Then, the average velocity can be calculated as follows:

vavg = s/t

Have a nice day!

6 0

2 years ago

Momentum is a vector quantity because it includes velocity, which is also a

zvonat [6]

Answer: A; True

Explanation: Momentum is known to be a vector quality, and thus has been proven by modern scientists and resulting in this answer being true.

Hope this helps <3

Stay safe, stay warm

-Carrie

Ps. it would mean a lot if you marked brainliest (=

7 0

2 years ago

Which two ways dose inertia affect the monitors of the planets

dedylja [7]

Answer:

the inertia provides the tendency to maintain speed and keep moving

7 0

1 year ago

Why do electrons flow threw a wire

Zolol [24]

Answer:

When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor. Electrons will move toward the positive side.

3 0

1 year ago