Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to incandescence for long periods of time. natural thorium is almost 100% 232th, with a half-life of 1.405 ✕ 1010 y. if an average lantern mantle contains 200 mg of thorium, what is its activity (in bq)?

The activity is 811.77 Bq

Solution:

As per the question:

Half life of Thorium,

Mass of Thorium, m = 200 mg = 0.2 g

M = 232 g/mol

Now,

No. of nuclei of Thorium in 200 mg of Thorium:

where

= Avagadro's number

Thus

Also,

Activity is given by:

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.