Which is more powerful- atomic bomb or hydrogen bomb? why?

They are both atomic bombs, and the hydrogen bomb is more powerful, because more energy is released during fusion than fission.

A hydrogen bomb is much more powerful, which is why its development escalated the Cold War. In a thermo-nuclear explosion, an atomic explosion is used to compress and ignite a fusion reaction. Because it compresses the second reaction, it is overwhelmingly more explosive when the energy is released.

Bear in mind that much of the knowledge about H bombs are educated speculation, as details are classified and never confirmed or denied.

They are both the same if measured in comparable kilotons of destructive force. And the atomic bomb explodes while the hydrogen bomb implodes. But the hydrogen bomb is more destructive, pound for pound, than the atom bomb because you can pack more destructive force in the basic delivery container.

Have a read here: First atomic bombs: http://www.atomicheritage.org/history/little-boy-and-fat-man
(I love science history and when I talk to people about the Manhattan Project and they don’t know what it was I get really upset for some reason.)

Here is an article that actually compares the H-bomb with the A-Bomb http://www.livescience.com/53280-hydrogen-bomb-vs-atomic-bomb.html

You can think of A-bombs as the fuse to light off the much bigger H-bomb – like a primer that initiates a ‘dynamite’ charge.

There are experimental labs all around the country working to initiate and contain fusion reactions. There is a lab in this region that detonates ~1mm hydrogen pellets at the triple point (~15K, -430 F! ) by slamming a burst from dozens of laser beams at it. They achieve fusion for an incredibly short time, but that burst produces on the order of the same power as the entire US energy grid! They can and do fire this baby off as many as 8 times per day! Holy Fusion, Batman!

It is one person’s job to make those pellets. How do you put that on a resume?

You can think of A-bombs as the fuse to light off the much bigger H-bomb

And in the most powerful designs , the H-bomb creates another bigger A-bomb explosion.

1) Conventional explosion
2) sets off fission explosion (A-bomb)
3) which sets off fusion explosion (H-bomb)
4) which causes the uranium casing to fission (A-bomb)

The atomic bomb dropped on Shima hospital in Hiroshima was the equivalent of 16 kilotons of TNT. The largest hydrogen bomb to be detonated was 4,000 times as powerful. Hydrogen bombs are fusion reactions which convert more matter to energy than fission and so can be made much more powerful.

Hydrogen bombs are much more powerful. An atomic bomb is the fuse that ignite a hydrogen bomb. Atomic bombs use fission of uranium for energy, while hydrogen bombs use fusion of hydrogen. More energy is involved in fusion than in fission. E = mc squared is the formula, and m (mass) is greater in fusion of hydrogen.