MYTUTOR SUBJECT ANSWERS

308 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...

2 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

48 SUBJECT SPECIALISTS

£20 /hr

Marcin K.

Degree: MPHYS Theoretical Physics (Masters) - Leeds University

Subjects offered: Physics, Music+ 1 more

Physics
Music
Maths

“Hi! Who am I? My name is Marcin and I am currently in my fourth year studying Theoretical Physics at the University of Leeds. I share my energy between two passions which are science and music. Learning about how the physical world ...”

MyTutor guarantee

£20 /hr

Dominic D.

Degree: MSci Theoretical Physics (Masters) - Birmingham University

Subjects offered: Physics, Maths+ 1 more

Physics
Maths
Further Mathematics

“Hi, I'm Dom, a third year Theoretical Physics student at the University of Birmingham. I have always been fascinated by the rich subjects that are maths and physics and look to convey that enthusiasm in my teaching. I have previous ...”

MyTutor guarantee

£22 /hr

Jonathan P.

Degree: Physics (Masters) - Durham University

Subjects offered: Physics, Maths

Physics
Maths

“About Me: I am a Physics student at Durham University. My passion is physics, and by association maths, I will aim to instil asimilar passion in students during my tutorials. I am a highly patient and approachable individual.  I have...”

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

Explain the workings of a mass spectrometer

What is the Doppler Effect?

What are the 'rules' of oscillation?

What is the Schwarzschild radius of a black hole?

View A Level Physics tutors

Cookies:

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

mtw:mercury1:status:ok