exam1fall2000

# exam1fall2000 - ". f c .. , *".~ .",;;,~...

This preview shows pages 1–2. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ". f c .. , *".~ .",;;,~ ENSC 3313, Fall 2000 Name Answe oints each. 1. Tritium is used in all modem American nuclear weapons, but needs to be periodically replaced because it .has a halflife of 12.3 years. The US used to make tritium in up to 14 nuclear reactors all of which have closed down since 1988. They will need new supplies after 2011. Congress wishes to build a new reactor in South Carolina. Assuming tritium was 'made' in 1988, what proportion has decayed by the year 2011 ? " TEST 1 .t !:.1. = e-tlA Ao Substituting, 0.5 = e-12.3/A A = 17.75 Repeating ~ = e-23/17.75 = 0.27 o 0.27 left, hence Q.L2 decayed (73% ) Wavelengths shorter than 225 nanometers are strongly ab~orbed by the valence electrons of diamond's carbon atoms, which then move to the conduction band and can produce a "response" signal. What band gap, E," (energy change L\E) does this correspond to? Answer in electron volts please. Know that Planck's constant, h = 0.662 x 10-33 J.s, and leV = 0.160 x 10-18 J. The velocity of light = 0.299 x 109 m/s....
View Full Document

## This note was uploaded on 01/10/2012 for the course ENSC 3313 taught by Professor Staff during the Fall '11 term at Oklahoma State.

### Page1 / 4

exam1fall2000 - ". f c .. , *".~ .",;;,~...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online