Which of the following describes the physical effects experienced during a nuclear air blast?

The correct answer highlights that a nuclear air blast produces both a shockwave and thermal radiation. When a nuclear weapon detonates in the atmosphere, it creates an immense amount of energy, which results in a rapid expansion of air. This expansion generates a powerful shockwave that can travel great distances, causing destruction to buildings, infrastructure, and anything in its path.

Additionally, thermal radiation is emitted during the explosion, which results in intense heat and can ignite fires over a wide area. This heat can cause severe burns and ignite flammable materials even at significant distances from the blast site.

Considering the other options, sound waves do occur during a nuclear explosion, but they are not the primary focus compared to the shockwave. Fireballs are produced as well but are more associated with the initial explosion rather than the broader physical effects. Radiation and debris are certainly concerns after a nuclear blast, but they are consequences of the explosion rather than immediate physical effects like the shockwave and thermal radiation. Flooding and electrical surges are not relevant to nuclear air blasts, but rather associated with other types of disasters such as hurricanes or electrical failures.