Answer : When a person applies force and covers distance then the person is doing work on an object.
Complete Question:
When specially prepared Hydrogen atoms with their electrons in the 6f state are placed into a strong uniform magnetic field, the degenerate energy levels split into several levels. This is the so called normal Zeeman effect.
Ignoring the electron spin what is the largest possible energy difference, if the magnetic field is 2.02 Tesla?
Answer:
ΔE = 1.224 * 10⁻²² J
Explanation:
In the 6f state, the orbital quantum number, L = 3
The magnetic quantum number, 
The change in energy due to Zeeman effect is given by:

Magnetic field B = 2.02 T
Bohr magnetron, 

ΔE = 1.224 * 10⁻²² J
There is a gel (agarose) that is placed in abuffer-filled box and an electrical
field is applied via a power supply. The negative terminal
is at the far end (black wire), this causes DNA migrates toward the anode (red
wire).