A radioactive isotope has a half-life of 5,000 years. A rock originally contained 16 grams of radioactive isotope, and now contains 4 grams. Approximately how many years old is the rock?

10,000 years

Explanation:

Given that,

Half life of the radioactive isotope, = 5000 years

Initial composition, = 16 grams

Final composition, = 4 grams

We know that,

Therefore, the age of the rock is 10,000 years.

96.77 amp

explanation:

rl = 250/100 = 2.5 ohms.

egl = 250 + (100 × 0.1) + 2 = 262 v.

at 700 r.p.m., eg2 = 262 × 700/1000 = 183.4 v.

if ia is the new current, then eg2 - 2 - (ia × 0.1) = 2.5 ia

which means this will give ia = 96.77 amp.