What Is the Difference Between a Hydrogen Bomb and an Atomic Bomb?

 A hydrogen bomb and an atomic bomb are both types of nuclear weapons, but the two devices are very different from each other. In a nutshell, an atomic bomb is a fission device, while a hydrogen bomb uses fission to power a fusion reaction. In other words, an atomic bomb can be used as a trigger for a hydrogen bomb.

Atomic Bomb

An atomic bomb or A-bomb is a nuclear weapon that explodes due to the extreme energy released by nuclear fission. For this reason, this type of bomb is also known as a fission bomb. The word "atomic" isn't strictly accurate since it's just the nucleus of the atom that is involved in fission (its protons and neutrons), rather than the entire atom or its electrons.

A material capable of fission (fissile material) is given supercritical mass, while is the point at which fission occurs. This can be achieved by either compressing sub-critical material using explosives or by shooting one part of a sub-critical mass into another one. The fissile material is enriched uranium or plutonium. The energy output of the reaction can range to the equivalent of about a ton of the explosive TNT up to 500 kilotons of TNT. The bomb also releases radioactive fission fragments, which result from the heavy nuclei breaking into smaller ones. Nuclear fallout mainly consists of fission fragments.

Hydrogen Bomb

A hydrogen bomb or H-bomb is a type of nuclear weapon that explodes from the intense energy released by nuclear fusion. Hydrogen bombs may also be called thermonuclear weapons. The energy results from the fusion of isotopes of hydrogen—deuterium and tritium. A hydrogen bomb relies on the energy released from a fission reaction to heat and compress the hydrogen to trigger fusion, which can also generate additional fission reactions. In a large thermonuclear device, about half of the yield of the device comes from fission of depleted uranium.

The fusion reaction doesn't really contribute to fallout, but because the reaction is triggered by fission and causes further fission, H-bombs generate at least as much fallout as atomic bombs. Hydrogen bombs can have much higher yields than atomic bombs, equivalent to megatons of TNT. The Tsar Bomba, the largest nuclear weapon ever detonated, was a hydrogen bomb with a 50 megaton yield.

The following link shows how hydrogen bomb really works -

https://youtu.be/8CH4OMUmOao

Comparisons

Both types of nuclear weapons release vast quantities of energy from a small amount of matter and release most of their energy from fission, and produce radioactive fallout. The hydrogen bomb has a potentially higher yield and is a more complicated device to construct.