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tiny-mole [99]
3 years ago
6

Calcium-51 has a half-life of 4.5 days. Only 0.75 gram remains of a sample that was initially 12 grams. How old is the sample of

calcium-51?
Physics
2 answers:
Over [174]3 years ago
6 0
How many times did the original sample lose 50% of its radioactivity ?

-- Start with. . . . . . . . . . . . 12 grams.
-- Lose half of it once. . . . . . 6 grams left.
-- Lose half of it again . . . . . 3 grams left.
-- Lose half of it again . . . . . 1.5 grams left.
-- Lose half of it again . . . . . 0.75 gram left.

-- How many times did it lose half ?    4 times.

-- How long does it take to lose half ?  4.5 days. 
                                                       (That's why it's called the 'half-life'.)

-- How long did it take to lose half, 4 times ?

                                           (4 x 4.5 days) = 18 days .
tatiyna3 years ago
3 0

Answer:

18 days

Explanation:

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What is kinematics?<br>explain!!~​<br><br>thankyou ~
Hatshy [7]

Answer:

<u>Kinematics:-</u>

  • Branch of mechanics concerned
  • Features of motion in an object
  • Causes and effects of motions

Hope it helps!

6 0
2 years ago
Read 2 more answers
If a change is made to a system in equilibrium, the equilibrium will shift to oppose the change.
Aleksandr [31]

Answer:

No

Explanation:

Because it won’t

5 0
3 years ago
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Glass absorbs ultraviolet (UV) rays from the Sun. Would a fraction of the incident UV light be reflected from the air/glass boun
fiasKO [112]

Answer:

Yes

Explanation:

Any transparent surface in practical is neither a perfect absorber of electromagnetic waves neither a perfect reflector. Generally all the transparent surfaces reflect some amount of irradiation and the other parts are absorbed and transmitted.

<u>That is given by as relation:</u>

\alpha+\rho+\tau=1

where:

\alpha= absorptivity which is defined as the ratio of the absorbed radiation to the total irradiation

\rho= reflectivity is defined as the ratio of reflected radiation to the total irradiation

\tau= transmittivity is defined as the ratio of total transmitted radiation to the total irradiation

6 0
3 years ago
A potential difference of 24 V is applied to a 150-ohm resistor. How much current flows through the resistor?​
Lady_Fox [76]

Given :- A resistor of 150 ohm, hence Resistance (R) = 150 ohm

Potential Difference (v) = 24 V

Current (I) = ?

V = IR

24 = I × 150

I = 24/150

I = 0.16 ampere

hope it helps!

3 0
3 years ago
What are the differences and relationships between speed, velocity, and acceleration
melamori03 [73]

Velocity is the rate of change of position with respect to time, whereas acceleration is the rate of change of velocity. Both are vector quantities (and so also have a specified direction), but the units of velocity are meters per second while the units of acceleration are meters per second squared.

3 0
3 years ago
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