E (c) Technetium-99m has a half-life of 6 hours.
Home work.
A sample of technetium-99m has an activity of 420 MBq.
(i) Explain why the activity of a radioactive sample reduces with time.

(ii) Calculate the activity of the technetium-99m sample after 24 hours.

pe = weightxheight = 2000x1000=2,000,000joules

wavelegth as in spectrum red oygbiv

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.

at right angles to each other