Which picture best illustrates thermal energy transfer by conduction? 1. Warming hand next to fire
2. Metal spoon in hot water
3. The sun warming the earth
4. Air warming above a radiator in a room

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

Particles vibrate in a rigid structure and do not move relative to their neighbors.

Adeuteron, 21h, is the nucleus of a hydrogen isotope and consists of one proton and one neutron. the plasma of deuterons in a nuclear fusion reactor must be heated to about 3.02×108 k . what is the rms speed of the deuterons? express your answer using two significant figures.