Advertisements
Advertisements
प्रश्न
Consider a quantity of a radioactive substance. The fraction of this quantity that remains after t half-lives can be found by using the expression 3–t. After how many half-lives will the fraction be `1/243` of the original?
Advertisements
उत्तर
Given, t half-lives = 3–t
So, `1/243 = 3^-t`
⇒ `1/3^5 = 1/3^t` ...`[because 3 xx 3 xx 3 xx 3 xx 3 = 3^5 "and" a^-m = 1/a^m]`
On comparing both sides, we get
t = 5 half-lives
APPEARS IN
संबंधित प्रश्न
Express the given numbers in usual form.
3.02 × 10-6
In a stack, there are 5 books each of thickness 20 mm and 5 paper sheets each of thickness 0.016 mm. What is the total thickness of the stack?
Express the following numbers in standard form:
6020000000000000
Express the following numbers in standard form:
0.00000000000943
Write the following numbers in the usual form:
3 × 10−8
Express the following number in the usual form.
The standard form for 0.000037 is 3.7 × 10–5.
Express `(1.5 xx 10^6)/(2.5 xx 10^-4)` in the standard form.
Pluto is 59,1,30,00,000 m from the sun. Express this in the standard form.
About 230 billion litres of water flows through a river each day. How many litres of water flows through that river in a week? How many litres of water flows through the river in an year? Write your answer in standard notation.
