MYTUTOR SUBJECT ANSWERS

1285 views

Uranium -238 has a half life of 4.5 billion years. How long will it take a 2g sample of U-238 to contain just 0.4g of U-238?

 

Radioactive decay is a process where the nucleus of an unstable atom, such as Uranium-238 loses energy by emitting radiation.

The half life is the average time it take for half the nuclei in a sample to undergo radioactive decay.

Given an initial sample of x with mass N(0). After a time t the mass of x left in the sample N(t) is given by:

N(t) = N(0).2-t/t1/2                (1)

Where t1/2 is the halflife. 

To answer the question we need to find t. Rearranging equation (1) we have:

- t1/2log2[N(t)/N(0)] = t          (2)

subbing the values from the question into (2)

-4.5x10* log2 [0.4/ 2] = 10.4 billion years

 

Robert E. A Level Physics tutor, GCSE Physics tutor, GCSE Maths tutor...

3 years ago

Answered by Robert, who tutored A Level Physics with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

101 SUBJECT SPECIALISTS

£20 /hr

Giorgos A.

Degree: Mechanical Engineering with Renewable Energy (Masters) - Edinburgh University

Subjects offered:Physics, Maths

Physics
Maths

“Feel rewarded helping younger students. Nobody is born knowing everything, life is a learning process and my aim is to help you achieve your goals.”

Trusted by schools

|  5 completed tutorials

£24 /hr

Ayusha A.

Degree: BEng electrical and electronics engineering (Bachelors) - Newcastle University

Subjects offered:Physics, Maths+ 1 more

Physics
Maths
Further Mathematics

“About me: I am a final year Electrical and Electronic Engineering student at Newcastle University. I took Mathematics, Further Mathematics, Chemistry and Physics as my A-level subjects. I did peer mentoring in university and also have...”

£20 /hr

Katherine R.

Degree: Physics (Bachelors) - Durham University

Subjects offered:Physics

Physics

“I am a Natural Sciences student at Durham University who specialises in Physics so I love talking about all things to do with science! I hope in my tutorial you will enjoy talking with me about everything from stars and galaxies to th...”

About the author

£20 /hr

Robert E.

Degree: Physics MSci (Masters) - Bristol University

Subjects offered:Physics, Maths

Physics
Maths

“Hi I'm Rob. I graduated with a Masters in Physics from the University of Bristol in 2014. Looking to tutor GCSE and A-Level Maths and Physics. ”

MyTutor guarantee

You may also like...

Other A Level Physics questions

Give examples of how the photoelectric effect supports the particle nature of light and defies the wave theory.

Is Pluto a planet?

How can I find out the Young's modulus of a material?

Explain in terms of the motion of the molecules of the gas why the volume of gas must increase if the pressure is to remain constant as the gas is heated.

View A Level Physics tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok