How many quantum states are possible for an atomic electron for which n = 4?
how many quantum states are possible for an atomic electron for which n = 2 and m = 0?
find the de broglie wavelength of an electron accelerated across a 22,600 v potential difference in a tv tube.
a geiger counter reading of a radioactive sample is initially 7220 counts per minute. the same sample gives a reading of 402 counts per minute 10.9 h later. what is the sample's half-life?
if a rock containing u-238 initially reads 64.4 counts per minute on a geiger counter, what will its reading be 3 weeks later?
find the activity of a sample containing 8.73 multiply. gif 1014 iodine-131 nuclei (t1/2 = 8.0 days)
find the activity of a sample containing 5.91 multiply. gif 10-6 g of _27^60 text(co) (t1/2 = 5.27 years).
find the binding energy and the binding energy per nucleon of the _92^238 text(u) nucleus

The following statements are about the electroscope. select all that are true. if an electroscope were given a positive charge beforehand, the leaves would move closer together if a positively charged object were brought near. when a properly prepared electroscope is used to determine the type of charge on an object, the total charge on the electroscope changes when the charged object is brought near (but not touching) the electroscope. depending on how the electroscope is prepared beforehand, the leaves can either move together or move apart when negative charge is brought near. an electroscope must first be given a known type of charge before it can be used to identify the types of charges on objects brought near it. when properly prepared, the leaves on an electroscope will always move further apart when negative charge is brought near. the leaves of an electroscope will move apart if it is given either a positive or a negative charge.