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A sample of an unknown radioisotope exhibits 8540 decays per second After 350 minutes the number of decays has decreased to 1250 per second What is the half life?
The decay rate N at time t is N(t)=N(0) x 2^-(t/t_half), where t_half is the half life and N(0) is the decay rate at t=0. The ^ means "to the power of."
You can solve this for t_half:
t_half = - t / log_2(N(t)/N(0)) (log_2 means logarithm base 2)
N(350 minutes)=1250, N(0)=8540. The rest is just finding a calculator to give you log_2 of 1250/8540.
What else can I help you with?
What is an unknown number decreased by six?
An unknown number decreased by six can be represented algebraically as ( x - 6 ), where ( x ) is the unknown number. This expression indicates that six is subtracted from the value of ( x ). The result is a new value that is six less than the original unknown number.
What is the equation for nine decreased by three times a number is the same as five times the sum of an unknown number and five?
The equation can be expressed as: ( 9 - 3x = 5(y + 5) ), where ( x ) is the unknown number being decreased and ( y ) is the unknown number being summed with five. This states that nine decreased by three times ( x ) is equal to five times the sum of ( y ) and five.
What is the algebraic expression for a number decreased by 8?
The algebraic expression for a number decreased by 8 can be represented as ( x - 8 ), where ( x ) is the variable representing the unknown number. This expression indicates that 8 is subtracted from the value of ( x ).
5 times an unknown number decreased by the same unknown number is less than the opposite of the sum of the unknown number and 5. What is the number?
The answer is 1. 5 times x - x < 5 + x It has to be 1, anything over 1 could not be less than.
What is Nine times a number decreased by four?
Nine times a number decreased by four can be expressed mathematically as ( 9x - 4 ), where ( x ) represents the unknown number. This expression indicates that you first multiply the number by nine and then subtract four from the result.
What is an unknown number decreased by six?
An unknown number decreased by six can be represented algebraically as ( x - 6 ), where ( x ) is the unknown number. This expression indicates that six is subtracted from the value of ( x ). The result is a new value that is six less than the original unknown number.
What is the equation for nine decreased by three times a number is the same as five times the sum of an unknown number and five?
The equation can be expressed as: ( 9 - 3x = 5(y + 5) ), where ( x ) is the unknown number being decreased and ( y ) is the unknown number being summed with five. This states that nine decreased by three times ( x ) is equal to five times the sum of ( y ) and five.
How do you write a number decreased by 16 in algebraic expression?
If x is the unknown variable then it can be: x-16
What is the algebraic expression for a number decreased by 8?
The algebraic expression for a number decreased by 8 can be represented as ( x - 8 ), where ( x ) is the variable representing the unknown number. This expression indicates that 8 is subtracted from the value of ( x ).
What is five times an unknown number decreased by the same unknown number is less than the opposite of the sum of the unknown and five?
Opposite of the sum is not a mathematical expression and I can only assume it means the difference.So,5x - x < |x - 5|Or 4x
5 times an unknown number decreased by the same unknown number is less than the opposite of the sum of the unknown number and 5. What is the number?
The answer is 1. 5 times x - x < 5 + x It has to be 1, anything over 1 could not be less than.
What is Nine times a number decreased by four?
Nine times a number decreased by four can be expressed mathematically as ( 9x - 4 ), where ( x ) represents the unknown number. This expression indicates that you first multiply the number by nine and then subtract four from the result.
How do you write 125 decreased by a nmber in a algebric expressin?
To express "125 decreased by a number" in algebraic form, you can use the variable ( x ) to represent the unknown number. The algebraic expression would be written as ( 125 - x ). This indicates that you are subtracting the value of ( x ) from 125.
If the product of a number and 8 is divided by 2 and decreased by 10the answer is 14 What is the unknown number?
8x/2 - 10 = 148x/2 = 248x = 48x = 6
What is the expression for eleven decreased by a number?
The expression for eleven decreased by a number can be written as 11 - x, where x represents the unknown number being subtracted from eleven. This expression represents the operation of subtraction, where the value of x will determine the final result after subtracting from eleven.
What are the release dates for 60 Minutes - 1968 Confessions of a Tobacco Lobbyist Causes Unknown Kurt Masur 27-27?
60 Minutes - 1968 Confessions of a Tobacco Lobbyist Causes Unknown Kurt Masur 27-27 was released on: USA: 19 March 1995
Can humans predic earthquakes?
Yes they can but only a couple of minutes before it strikes. Scientists know where earthquakes could occur but the when is unknown until a few minutes beforehand.
