Give the definitions of the following notions

1. closed energy cycles
2. radioactive-energy-release
3. conservation of energy
4. natural precursor
5. natural radioactivity
6. threshold gamma-ray energy
7. excess mass
8. mass spectroscopy

Work in 2 groups. Read the text again and extract the information required for the chosen theme (1-2) and start discussion.

Energy release in radioactive transitions

1. Calculation and measurement of energy

LISTENING

WHY SHOULD WE SIT FAR FROM THE TV?

1. You are going to listen to a podcast where Andy Karam, adjunct professor at the Rochester Institute of Technology tries to answer the following question:

‘When I was younger I was told not to sit too close to the TV. Is it an urban myth that it's dangerous to sit too close? Or does the TV emit radiation? Does this still apply to modern televisions? Claudia, Argentina’

What would you answer if you were asked this question?

For questions below choose the correct answer.

Which type of TV emits the most radiation?

a) plasma

b) cathode ray tube

c) LCD

What type of radiation are you exposed to when you watch TV?

a) X-rays

b) neutron radiation

c) alpha radiation

What is the main hazard of sitting close to the TV?

a) receiving a high dose of ionizing radiation

b) damaging your eyesight

c) getting a heart disease

Listen to the podcast and check your guesses.

Listen again and fill in the gaps according to what you hear.

a. What happens is that anything with a cathode ray tube, a tube where you shoot _____________ electrons at some sort of screen, when those electrons hit the screen, they give off very low energy x-ray radiation.

b. Now having said that, I’ve got to emphasize, they're __________ of radiation.

c. I could not say that they're safer because I don't consider the radiation from cathode ray tubes to be a risk, but I can say that they _________ less radiation.