Numerical chapter 18 class 10 | 18.1, 18.2, 18.3, 18.4, 18.5 | 10th class physics ch 18 numerical

Thermal expansion class 9 | class 12 | Linear thermal expansion in solid | volume thermal expansion 18.1. The half-life of is 7.3 s. A sample of this nuclide of nitrogen is observed for 29.2 s. 16 7N Calculate the fraction of the original radioactive isotope remaining after this time. Ans. (1/16) 18.2. Cobalt-60 is a radioactive element with half-life of 5.25 years. What fraction of the original sample will be left after 26 years? Ans. (1/32) 18.3. Carbon-14 has a half-life of 5730 years. How long will it take for the quantity of carbon-14 in a sample to drop to one-eighth of the initial quantity? 4 Ans. (1.72 × 10 years) 18.4. Technetium-99 m is a radioactive element and is used to diagnose brain, thyroid, liver and kidney diseases. This element has half-life of 6 hours. If there is 200 mg of this technetium present, how much will be left in 36 hours. Ans.(3.12 mg) 18.5. Half-life of a radioactive element is 10 minutes. If the initial count rate is 368 counts per minute, find the time for which count rates reaches 23 counts per minute. Ans. (40 minut