Deposited energy over mass sets unshielded and shielded dose. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Three kilograms turns twelve joules into four

Before shielding, 12 joules over 3 kilograms gives dose 4 joules per kilogram. After shielding, 3 joules gives 1 joule per kilogram.

12÷3=43÷3=112\div3=4\quad3\div3=1
Dose scan rowEnergy, mass, and dose labels are checked.massbeforeafterbefore E=12 Jafter E=3 Jmass=3 kgbefore dose=4 J/kgafter dose=1 J/kg

More energy and mass can keep the dose

Before shielding, 20 joules over 5 kilograms gives dose 4 joules per kilogram. After shielding, 5 joules gives 1 joule per kilogram.

20÷5=45÷5=120\div5=4\quad5\div5=1
Dose scan rowEnergy, mass, and dose labels are checked.massbeforeafterbefore E=20 Jafter E=5 Jmass=5 kgbefore dose=4 J/kgafter dose=1 J/kg

Same mass with more energy raises dose

Before shielding, 18 joules over 3 kilograms gives dose 6 joules per kilogram. After shielding, 6 joules gives 2 joules per kilogram.

18÷3=66÷3=218\div3=6\quad6\div3=2
Dose scan rowEnergy, mass, and dose labels are checked.massbeforeafterbefore E=18 Jafter E=6 Jmass=3 kgbefore dose=6 J/kgafter dose=2 J/kg