Question 40 unsaved if heat energy is transferred from direct contact between a warm object and a cold object, it has been transferred by question 40 options: 1) the sun 2) convection 3) conduction 4) radiation

3) conduction

Explanation:

Conduction is the process of heat transfer between solids, which require a material medium for its propagation. And in this case, heat would flow from the warm object to the cold one when in contact until they both reach a state of thermal equilibrum (neglecting heat loss to the surrounding).

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.