Question

6. The half life of Uranium-238 is 4.5 x 109 years. The half-life of Uranium-234 is 2.5 x 10 years. How many
times greater is the half life of U-238 than that of U-234?
7. A speck of dust in an electron microscope is 1.2 x 102 mm wide. The image is 5 x 102 times larger than the
actual size. How many millimeters wide is the actual speck of dust?
the​

Answer 1

The half life of uranium - 238 is 4.5 *10 years The half life of uranium - 234 is 25 * 105 years 20000 time grater 6

Answer 2

Answer :-

6. Uranium - 238 = 4.5*109 = 490.5 years

Uranium - 234 = 2.5*10 = 25 years

No. of times U-238 than U-234 = $\frac{Uranium - 238 half life}{Uranium - 234 half life}$

                                                    = $\frac{490.5}{25}$

                                                    = 19.62 times

7. Width of the electron = 1.2*102

                                       = 122.4mm