2 g of a radioactive sample having half life of 15 days was synthesised on 1st Jan 2009. The amount of the smaple left behind on 1st March, 2009 (including btoh the days)

Options

A. 0.125 g
B. 1 g
C. 0.5 g
D. 0 g

Answer

A

Explanation

No of days from 1st jan 09 to 1st March 09
`=60`
given `t_(1//2)=15` days
total time `T=60` days
`:.`no of half lives n=?
`T=nxxt_(1//2)implies60=nxx10impliesn=4`
Also given initial amount of sample `N_(0)=2g `
`:. ` sample present after 4 half lives N=?
`N=(1/2)^(n)N_(0)`
`impliesN=(1/2)^()xx2=2/16=0.125g`