Answer to Question #61367 in Electricity and Magnetism for bebeji

Question

19) The half-life of a certain radioactive isotope is 32 hours. What fraction of the sample would remain after 16 huors?
a) 0.50
b) 0.25
c) 0.62
d) 0.71
20) A potentiometer wire of length 100cm has a resistance of 10Ê. It is connected in series to to a resistance R and a cell of emf 2V and negligible internal resistance. A source of emf of 10mV is balanced by a length of 40cm of the potentiometer wire. What is the value of the resistance R?
a) 200Ê
b) 950Ê
c) 2000Ê
d) 790Ê