Atomic and Nuclear Physics Answers

number of spectral lines when electron jumps from n=4 to ground state if two atoms are present in the sample

does critical mass has different ranges. i mean different packets of critical masses

what is the wave length of an alpha particle

Is shadow a matter? If yes then which form of matter?

Is the following statement true? "All Isotopes are Atoms, but not all Atoms are Isotopes"

what is atom?

a body is thrown vertically upwards with initial velocity of 100m/s find (1)time taken to reach at maximum height (2)maximum height attend (3)velocity after 5 second (4)velocity after 16 second. Take (a=10m/s2)

classify elementary particles.

if a radioactive material has a half-life of 2 years, a sample is reduced to 1/8 of its mass in?

quantum physics states that electrons can act as a wave or a particle. I thought they meant that the particle would be moving in a sine wave, but they told me that that was not the case. that the particles acted like waves in an ocean or something like that. I do not understand this at all, and I need a basic understanding of quantum physics by next fall. So, can someone please explain the particle or wave thing to me.