Which of the following is not an example of a transmutation? a. uranium-238 emits an alpha particle forms thorium-234 b. uranium-238 is bombarded with a neutron to produce uranium-239 c. potassium-38 emits a beta particle and forms argon-38 d. plutonium-239 is bombarded with two neutrons to produce americium-241 and a beta particle

The right option is (C).

The potassium-40 is the isotope of potassium which has the half-life of 1.251×109 years to reduce its half quantity. There are rare elements present on earth which follow the two type of beta decay. Potassium-40 is one of them which can decay as beta decay to convert into Ca-40 or electron capture decay to convert into the Ar-40. In this second decay, they also emit gamma rays. So, the right option is (C) which wrong regarding the transmutation.

vapour or gas assuming atmospheriv pressure

d) physical means can be used to separate the components of air.