Answer : The types of radiation known to be emitted by radioactive elements are, alpha particles, beta particles, or gamma rays.
Explanation :
Radioactive decay : It the process in which an unstable atomic nucleus loses energy by emitting the radiations like, alpha particles, beta particles, or gamma rays.
The naturally occurring radioactive elements are, radium, thorium, and uranium.
Alpha particle : It is also known as alpha radiation or alpha ray that consists of 2 protons and 2 neutrons that are bound together into a particle that is identical to the helium nucleus. It is produced in the process of alpha decay.
Beta particle : It is also known as beta radiation or beta ray. During the beta decay process, a high energy and speed electron or positron are emitted by the radioactive decay of atomic nucleus.
Gamma particle : It is also a gamma radiation or gamma ray that is arising from the radioactive decay of atomic nuclei. It has shortest wavelength waves and imparts high photon energy can pass through most forms of matters because they have no mass.
Answer:
-100 kJ
Explanation:
We can solve this problem by applying the first law of thermodynamics, which states that:

where:
is the change in internal energy of a system
Q is the heat absorbed/released by the system (it is positive if absorbed by the system, negative if released by the system)
W is the work done by the system (it is positive if done by the system, negative if done on the system)
For the system in this problem we have:
W = +147 kJ is the work done by the system
Q = +47 kJ is the heat absorbed by the system
So , its change in internal energy is:
