If fired 1200 Nuclear missiles to USA then how many minutes it will take to wipe out US name from the earth ???

You're not familiar with the doctrine of mutually assured destruction??

The US has three delivery mechanisms for retaliatory nukes.

#1 is bombers. Nuclear armed bombers scramble into the air if incoming threats are detected. This is the easiest mechanism to repel, because bombers can often be detected and shot down.

#2 is ICBMs (intercontinental ballistic missiles) in silos. ICBMs travel 8000 to 10,000 miles in about 15 minutes. The US has about 450 hardened launch silos (plus unknown dummies), and it requires an H bomb within about 100 ft to disable a silo. Most of the ICBMs carry MIRVs (multiple independently targeted re-entry vehicles) with 4 to 10 warheads each. Fail to disable a silo and you many have ten warheads right back at you.

#3 is submarines. Vanguard class carry 16 MIRV ICBMs with 10 warheads each. Ohio class carry 20. A single submarine thus carries enough warheads to send any group of nations back to the stone age. Our existing fleet of ballistic missile submarines currently carries 54 percent of our nation's nuclear deterrent arsenal.

So yes, Russia could wipe the US off the face of the Earth, and might last 20 minutes longer before it was also wiped off the face of the Earth, as well as several other countries if that's what the orders say. And that is what's known as "deterrence."

BTW, I find it odd that any adult in this day and age is unfamiliar with the doctrine of mutually assured destruction.

About 9 to 12 minutes. Cheers

Not sure that would be the best way to resolve the current discontent, plus there’s also the small matter of where to get those missiles, not to mention the ones they’d fire off in return.

Suggest you watch On the Beach (1959).

Ikr? And they think they are immune from wars

The United States has the best chance of surviving a nuclear attack. Russia has unreliable missiles to deliver with from a long and extensive sanction.
By that time all of NATO would retaliate. The U.S. also has a quiet sentry of submarines for any froggy nation.
Jump!

Why would 1,200 nukes be fired on the US?

Or why would any parties responsible for it expect to survive more than a few hours?

The first nuke fired in anger, will probably be the end of humanity.

Let's say the US is destroyed, do you think the fallout will be limited to the US?

It's impossible because you need a delivery system for all those...and after firing the first dozen or so you would also be wiped out. You can't do them all at once.

It's impossible for any of these country to win a nuclear war aganst the other. The U.S. could not win a nuclear war against China or Russia.

How many can detonate at once without leaving the earth uninhabitable? 🤔

This is in the wrong section! It should be under "War, Weapons & Battle".

It would wipe us out, and it would happen quickly, but whoever fired the missiles would get clobbered by return fire. And it's not possible to knock out our ability to launch nukes with a nuclear first strike because of submarines.

Mutually assured destruction is real. Once they launch, there will be nobody left to delete records…

Fired from Brazil? It wouldn't take long and then Brazil would cease to exist ...kind of defeats the purpose.

About the same amount of time it would take to wipe you out too.
They all would go off.

This is why there won’t be any female US presidents. Menstrual cycles with access to the big red button.