# Homework Help: Adiabatic Process of uranium fission bomb

1. May 31, 2010

### Creebe

1. The problem statement, all variables and given/known data
The fireball of a uranium fission bomb consists of a sphere of radius = 15m and temperature 300,000K shortly after detonation. Assuming that the expansion is adiabatic and that the fireball remains spherical, estimate the radius of the ball when the temperature is 3000K. (Take γ = 1.4)

2. Relevant equations

3. The attempt at a solution

2. May 31, 2010

### rock.freak667

What equations do you need here?

When you figure out the relevant equations, this becomes quite simple.

3. May 31, 2010

### Creebe

okay i did

$TV\exp{γ-1} = constant T = \frac{constant}{V\exp{γ-1}} dT = (1-γ)V\exp{-γ)dV$

4. May 31, 2010

### rock.freak667

ok right if you have TVγ-1= constant; then this means T1V1γ-1=T2V2γ-1. Right?

You can find V1 since you are given the radius and you know T1 and T2, so all you need to get really is V2

5. Jun 1, 2010

### Creebe

oohh that's what the constant means. Okay! thanks!!