Is Hydrogen Bomb (H-Bomb) the strongest? If so, can it destroy an entire city?

Question

Please, do not get all scientific and explain how an H-Bomb works, I already got the concept. All I reall want to know is how strong the H-Bomb is and how much area of ground an H-Bomb can destroy.

Answer 1

This is good as it gives a very good idea what is involved. Don't ask about "La Bomba". It's just too big to conside.

The fission bomb detonated over Hiroshima had an explosive blast equivalent to 12,500 tons of TNT. A 1 megaton hydrogen bomb, hypothetically detonated on the earth’s surface, has about 80 times the blast power of that 1945 explosion.

Radius of destructive circle: 1.7 miles

12 pounds per square inch

At the center lies a crater 200 feet deep and 1000 feet in diameter. The rim of this crater is 1,000 feet wide and is composed of highly radioactive soil and debris. Nothing recognizable remains within about 3,200 feet (0.6 miles) from the center, except, perhaps, the remains of some buildings’ foundations. At 1.7 miles, only some of the strongest buildings — those made of reinforced, poured concrete — are still standing. Ninety-eight percent of the population in this area are dead.

Radius: 2.7 miles

5 psi

Virtually everything is destroyed between the 12 and 5 psi rings. The walls of typical multi-story buildings, including apartment buildings, have been completely blown out. The bare, structural skeletons of more and more buildings rise above the debris as you approach the 5 psi ring. Single-family residences within this this area have been completely blown away — only their foundations remain. Fifty percent of the population between the 12 and 5 psi rings are dead. Forty percent are injured.

Radius: 4.7 miles

2 psi

Any single-family residences that have not been completely destroyed are heavily damaged. The windows of office buildings have been blown away, as have some of their walls. The contents of these buildings’ upper floors, including the people who were working there, are scattered on the street. A substantial amount of debris clutters the entire area. Five percent of the population between the 5 and 2 psi rings are dead. Forty-five percent are injured.

Radius: 7.4 miles

1 psi

Residences are moderately damaged. Commercial buildings have sustained minimal damage. Twenty-five percent of the population between the 2 and 1 psi rings have been injured, mainly by flying glass and debris. Many others have been injured from thermal radiation — the heat generated by the blast. The remaining seventy-five percent are unhurt.

1 Megaton Surface Blast: Fallout

One of the effects of nuclear weapons detonated on or near the earth’s surface is the resulting radioactive fallout. Immediately after the detonation, a great deal of earth and debris, made radioactive by the blast, is carried high into the atmosphere, forming a mushroom cloud. The material drifts downwind and gradually falls back to earth, contaminating thousands of square miles. This page describes the fallout pattern over a seven-day period.

Assumptions

Wind speed: 15 mph

Wind direction: due east

Time frame: 7 days

3,000 Rem*

Distance: 30 miles

Much more than a lethal dose of radiation. Death can occur within hours of exposure. About 10 years will need to pass before levels of radioactivity in this area drop low enough to be considered safe, by U.S. peacetime standards.

900 Rem

Distance: 90 miles

A lethal dose of radiation. Death occurs from two to fourteen days.

300 Rem

Distance: 160 miles

Causes extensive internal damage, including harm to nerve cells and the cells that line the digestive tract, and results in a loss of white blood cells. Temporary hair loss is another result.

90 Rem

Distance: 250 miles

Causes a temporary decrease in white blood cells, although there are no immediate harmful effects. Two to three years will need to pass before radioactivity levels in this area drop low enough to be considered safe, by U.S. peacetime standards.

*Rem: Stands for “roentgen equivalent man.” This is a measurement used to quantify the amount of radiation that will produce certain biological effects.

25 Megaton Air Blast: Pressure Damage

Radius of destructive circle: 6.5 miles

12 pounds per square inch

The remains of some buildings’ foundations are visible. Some of the strongest buildings — those made of reinforced, poured concrete — are still standing. Ninety-eight percent of the population within this area are dead.

Radius: 10.7 miles

5 psi

Virtually everything is destroyed between the 12 and 5 psi rings. The walls of typical multi-story buildings, including apartment buildings, are completely blown out. As you move from the center toward the 5 psi ring there are more structural skeletons of buildings standing. Single-family residences within this this area have been completely blown away — only their foundations remain. Fifty percent of the population between the 12 and 5 psi rings are dead. Forty percent are injured.

Radius: 20 miles

2 psi

Any single-family residences that are not completely destroyed are heavily damaged. The windows of office buildings have been blown away, as have some of their walls. The contents of these buildings’ upper floors, including the people who were working there, are scattered on the street. A substantial amount of debris clutters the entire area. Five percent of the population between the 5 and 2 psi rings are dead. Forty-five percent are injured.

Radius: 30.4 miles

1 psi

Residences are moderately damaged. Commercial buildings have sustained minimal damage. Twenty-five percent of the population between the 2 and 1 psi rings are injured, mainly by flying glass and debris. Many others have been injured from thermal radiation — the heat generated by the blast. The remaining seventy-five percent are unhurt.

Answer 2

Yes an H bomb is the strongest. The  answer to your next question would depend on the size of the bomb and the size of the city.

Answer 3

The most powerful man-made device in history was an H-Bomb.  Specifically it was a three-stage device built and detonated by the Soviet Union.  It had an explosive yield equivalent to 50 million tons of TNT.  It was nicknamed "Tsar Bomba" by the west.

At its peak volume the height of the mushroom cloud from Tsar Bomba was over 41 miles (66 km) and 27 miles (43.5 km) thick.  By comparison, the bomb that destroyed Hiroshima ("Little Boy") was estimated to be a mere 15 kilotons, or about only about 0.03% as powerful.  Tsar Bomba had a blast radius about 57.7 times larger than Little Boy.