in these options not any Element are liquid at 1000k i think you type wrong in first option It is Hg not Ag and Hg is liquid at 1000 k
An early model of the atom was developed in 1913 by Danish scientist Niels Bohr (1885–1962). The Bohr model shows the atom as a central nucleus containing protons and neutrons with the electrons in circular orbitals at specific distances from the nucleus . These orbits form electron shells or energy levels, which are a way of visualizing the number of electrons in the various shells. These energy levels are designated by a number and the symbol "n." For example, 1n represents the first energy level located closest to the nucleus.
Well, first of all, the formula for finding potential energy is;
PE=mgh
Where; m is the mass
g is the gravitational force or acceleration due to gravity
h is the height.
Anyway, according to the question, the mass is 1kg, the acceleration due to gravity has a constant value of 10ms² . And the height is 3m. Now you just have to use all these in the formula. So;
mgh= 1 x 10 x 3. That will be 30. And the unit of potential energy is Joule. So the answer is 30 joules. Hope i helped. Have a nice day.