Carbon has six protons. Which model shows a neutral atom of carbon?

A radioactive material has a count rate of 400 per minute. It has a half life of 40 years. How long will it take to decay to a r

cestrela7 [59]

Answer:

160 years.

Explanation:

From the question given above, the following data were obtained:

Initial count rate (Cᵢ) = 400 count/min

Half-life (t½) = 40 years

Final count rate (Cբ) = 25 count/min

Time (t) =?

Next, we shall determine the number of half-lives that has elapse. This can be obtained as follow:

Initial count rate (Cᵢ) = 400 count/min

Final count rate (Cբ) = 25 count/min

Number of half-lives (n) =?

Cբ = 1/2ⁿ × Cᵢ

25 = 1/2ⁿ × 400

Cross multiply

25 × 2ⁿ = 400

Divide both side by 25

2ⁿ = 400/25

2ⁿ = 16

Express 16 in index form with 2 as the base

2ⁿ = 2⁴

n = 4

Thus, 4 half-lives has elapsed.

Finally, we shall determine the time taken for the radioactive material to decay to the rate of 25 counts per minute. This can be obtained as follow:

Half-life (t½) = 40 years

Number of half-lives (n) = 4

Time (t) =?

n = t / t½

4 = t / 40

Cross multiply

t = 4 × 40

t = 160 years.

Thus, it will take 160 years for the radioactive material to decay to the rate of 25 counts per minute.

7 0

2 years ago

The Netherlands controlled ______ for centuries A. Vietnam B. Malaysia C. Indonesia

gogolik [260]

The Netherlands controlled Indonesia for centuries!

4 0

3 years ago

Read 2 more answers

What are the characteristics of an ideal transformer

Vsevolod [243]

It is an imaginary transformer which has no core loss, no ohmic resistance and no leakage flux. The ideal transformer has the following important characteristic. The resistance of their primary and secondary winding becomes zero. The core of the ideal transformer has infinite permeability.

4 0

3 years ago

The world's fastest production sportscar has a top speed of 415 kmh-1(a)Convert this speed to ms-1.[ 1](b)The distance from Lond

Alex73 [517]

Answer:

(a). The speed is 115.28 m/s.

(b). The time is 94 min.

(c). The International Space Station travels 43202.400 km.

(d). Speed is scalar quantity.

Velocity is vector quantity.

Explanation:

Given that,

Top speed = 415 km/h

1 miles = 1609 m

(a). We need to calculate the speed in m/s

Using conversion of km/h to m/s

$v=415\ km/h$

$v=415\times\dfrac{5}{18}$

$v=115.28\ m/s$

(b). We need to calculate the distance from London to Edinburgh in km

Using conversion for distance

$d=403\ miles$

Distance in meter,

$d=403\times1609$

$d=648427\ m$

$d=648.427\ km$

We need to calculate the time

Using formula of time

$t=\dfrac{d}{v}$

Put the value into the formula

$t=\dfrac{648.427}{415}$

$t=1.56\ h$

$t=1\ hours 34\ min$

$t= 94\ min$

(c). Speed v' =7.66 km/s

v'=7660 m/s

In the time it takes the car to travel from London to Edinburgh,

We need to calculate the distance

Using formula of distance

$d'=v'\times t$

Put the value into the formula

$d'=7660\times94\times60$

$d'=43202400\ m$

$d'=43202.400\ km$

(d). Speed :

Speed is equal to the distance divided by time.

It is scalar quantity.

Velocity :

Velocity is equal to the displacement divided by time.

It is vector quantity.

Hence, (a). The speed is 115.28 m/s.

(b). The time is 94 min.

(c). The International Space Station travels 43202.400 km.

(d). Speed is scalar quantity.

Velocity is vector quantity.

3 0

3 years ago

A girl and a boy pull in opposite directions on strings attached to each end of a spring balance. Each child exerts a force of 2

BabaBlast [244]

Answer:

yo they deleted my answer. The answer is 0N

Explanation:

so when two forces pull on an object from opposite sides with the same force (in this case its 20N), then the object is in equilibrium at 0N.

So its clear that there is one person on the the opposite side.

SOOO generally: (left or down) would be considered negative in an equation. And the other person (right or up) would be considered positive. So if both forces are the same numbers on opposite sides then the answer is 0 (if you add both of them).

0 is the number of equilibrium.

OK, so the equation would be -20N + 20N and then badda bing badda boom viola, the answer: 0N

thanks for coming to my TED talk. I hope they don't delete this answer.

5 0

3 years ago