What is the half-life of a radioisotope? a. half of the time needed for a sample of radioisotope to become stable
b. the time needed for half of a sample of radioisotope to decay
c. the time needed before the first half of a radioisotope begins to decay
d. half of the time needed for a radioisotope to leave the body

Write a hypothesis about the effect of increasing resistance on the current in the circuit. use theformat and be sure to answer the lesson question. “how do changes in voltage or resistance affect current in an electric circuit? ”

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. they are charged to ±10 nc. what is the electric field strength between the disks? a proton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?

Currents in dc transmission lines can be 100 a or higher. some people are concerned that the electromagnetic fields from such lines near their homes could pose health dangers. for a line that has current 150 a and a height of 8.0 m above the ground, what magnetic field does the line produce at ground level? express your answer in teslas and as a percentage of the earth’s magnetic field, which is 0.50 g. is this value cause for worry?