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It depends on your definition of “ancient.” Radiometric dating using Carbon-14 can reliably date back to about 50,000 years, uranium-lead or lead-lead dating can date back multiple millions, potassium-argon dating can reach 1.5 billion, and rubidium-strontium can reach 50 billion (nearly 4x the age of the universe). It depends on the context in which this question is being asked.
Answer:
(A) Speed will be 
(b) Change in kinetic energy =
Explanation:
We have given mass of proton 
Acceleration of the proton 
Initial velocity u =
m/sec
Distance traveled by proton s = 3.90 cm = 0.039 m
(a) From third equation of motion we know that



(b) Initial kinetic energy 
Final kinetic energy 
So change in kinetic energy 
The answer is n= 6.
What is Balmer series?
The Balmer series is the portion of the emission spectrum of hydrogen that represents electron transitions from energy levels n > 2 to n = 2. These are four lines in the visible spectrum. They are also known as the Balmer lines. The four visible Balmer lines of hydrogen appear at 410 nm, 434 nm, 486 nm and 656 nm.
For the Balmer series, the final energy level is always n=2. So, the wavelengths 653.6, 486.1, 434.0, and 410.2 nm correspond to n=3, n=4, n=5, and n=6 respectively. Since the last wavelength, 410.2 nm, corresponds to n=6, the next wavelength should logically correspond to n=7.
To solve for the wavelength, calculate the individual energies, E2 and E7, using E=-hR/(n^2). Then, calculate the energy difference between E2 (which is the final) and E7 (which is the initial). Finally, use lamba=hc/E to get the wavelength.
To learn more about emission spectrum click on the link below:
brainly.com/question/24213957
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B. Mining in the Guinean Forests of West Africa to provide diamond and gold jewelry for humans.