the same time as the light flash, leaving the observer little to no time to find cover from this aspect of a nuclear detonation, but subsequently some of this radiation is absorbed and re-emitted by heated fireball air molecules at lower wavelengths, so harmful ionizing radiation may continue for up to a minute during which time ducking and covering would go some way in limiting one's exposure. Alongside the misapprehension that all nuclear weapons have increased in yield to levels of the 50 Megaton Tsar Bomba, instead of the reality that the more militarily effective and numerous nuclear weapons are those akin to the W76 and Russian Bulava, which have a yield of approximately 100 to 200 kiloton(0.2 Megaton) and as it is these explosive devices that equip the submarine fleets of the US, Britain and Russia, it is therefore these explosive devices that are most likely to be encountered by civilians.<ref>Ch. 1: The Dangers from Nuclear Weapons: Myths and Facts – Nuclear War Survival Skills Today(1980s) few if any of Russia's huge intercontinental ballistic missiles (ICBMs) are armed with a 20-megaton warhead. Now a huge Russian ICBM, the SS-18, typically carries 10 warheads, each having a yield of 500 kilotons, each programmed to hit a separate target. See Jane's Weapon Systems, 1987–88.]</ref> The other similarly common misapprehension or criticism of duck and cover that is frequently encountered is the opinion that prompt ionizing radiation effects would still kill those who duck and cover, regardless of any preventive measures taken. However this is generally incorrect unless any nuclear weapon more powerful than 10–30 kilotons is detonated, and even in that case, if the person is indoors the absorbed radiation dose is again not life-threatening. For example, despite the film not being made in the era of megaton-range weapons, for exposed individuals taking no preventive countermeasures the range of harmful ionizing radiation effects stays within a circle of radius 2–3 km from ground zero during airbursts of 1 megaton in yield, yet the blast range that would be expected to be lethal to 50% of people is 7.5 km, and the range of thermal effects lethal to 50% of people stretching out to 11 km from ground zero. Naturally, within this 3 km range from a 1-megaton airburst, the fatality rate would be near total for those caught in the open from the extreme blast pressure alone, before any potential radiation