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NISA [10]
3 years ago
14

The half-life of uranium-235 is 713 million years. Suppose a rock originally had 26 grams of uranium-235. A geologist had the ro

ck tested, and found that it now has only 3.25 grams of uranium-235.
Approximately how old is the rock?
Physics
1 answer:
BlackZzzverrR [31]3 years ago
7 0

Answer:

<h3>2139 Million years</h3>

Explanation:

Half life of a material is the time required for the material to decay into half of initial amount.

initially there is 26 grams of uranium-235, and the final amount is 3.25 gram

                 ratio between initial and final amount = \frac{26}{3.25}  = \frac{1}{8}

now it is clear that the material have halved 3 times from initial condition

number of half lives passed = 3

number of half lives passed can also be found using the equation

                no of half lives = log_{2} \frac{R_{0} }{R}

where R_{0} is the initial amount of material and R is the final amount

∵ Number of half lives = log_{2} \frac{26 }{3.25}

                                      = 3

So, age of rock = half-life X number of half-lives passed

                          =713000000 X 3

                          = 2139000000

                          =2139 Million Years

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Answer:

Explanation:

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A car travels first 10 km in 20 minutes and another 10 km in 30 minutes. What is the average speed of the car in m/s?
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Total distance = 10 km + 10 km = 20 km

1 km = 1000 m

20km x 1000 = 20,000 m

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A step-up transformer has a primary coil with 100 loops and a secondary coil with 1,500 loops. If the primary coil is supplied w
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(a) The voltage that is produced in the secondary circuit is 1,800 V.

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<h3>Voltage in the secondary coil</h3>

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