I suppose that you think to the radioactive isotope Cs-17; After 4 years remain 9,122 g.
2 1/2 g
2 1/2 g
As you did not specify an isotope of cesium, I will assume you meant natural cesium. Natural cesium is not radioactive so it does not decay. There will always be the same 10 g of cesium, no matter how long you wait.
The equation for half-life is ... AT = A0 2 (-T/H) ... where A0 is the starting activity, AT is the activity at some time T, and H is the half-life, in units of T. 55134Cs has a half-life of 2.0652 years. Plugging in the known values, we get ... AT = 5.8 2 (-11.5/2.0652) AT = 5.8 2 -5.5685 AT = 0.12222
I suppose that you think to the radioactive isotope Cs-17; After 4 years remain 9,122 g.
2 1/2 g
2 1/2 g
2 1/2 g
2 1/2 g
2 1/2 g
After 6 years, approximately 5 grams of cesium-137 would remain from a 10 g sample due to its half-life of around 30 years. This decay is exponential, with about half of the original sample decaying every 30 years.
1 1/4 g (apex)or 1.25 g
11/4 g apex
2 1/2g
As you did not specify an isotope of cesium, I will assume you meant natural cesium. Natural cesium is not radioactive so it does not decay. There will always be the same 10 g of cesium, no matter how long you wait.
After 90 years, about 0.5 mg of cesium-137 would remain since cesium-137 has a half-life of about 30 years. This means that half of the initial amount would have decayed in 30 years and another half in the next 30 years, leaving around 0.5 mg after 90 years.