3 Points The half-value layer for lead for g rays from 60Co is 12.8 mm. An electrometer gave a count rate of 35 pulses per second when at a
certain distance from a source, with no lead between source and detector. If 6 mm of lead were then inserted between source and
detector, the count rate (in pulses per second) would be nearest to:
A. 16
OB. 8
OC. 20
D. 25
OE. 75

True or false: the revolution of the earth creates day and night as it rotates around the sun

What is the rate of 12 liters of water moving through a water hose in 4.0 minutes?

Point charges q1=+2.00μc and q2=−2.00μc are placed at adjacent corners of a square for which the length of each side is 1.50 cm . point a is at the center of the square, and point b is at the empty corner closest to q2. take the electric potential to be zero at a distance far from both charges. part a what is the electric potential at point a due to q1 and q2? express your answer with the appropriate units.