Which physicist, reflecting on the atomic bomb, reportedly said in 1955, "If only I had known, I would have become a watchmaker"?

A photic sneeze is triggered by what? Where does a photographer go "to see what develops"? A phrase in Longfellow's "Paul Revere's Ride" gave its title to which 1996 Sandra Bullock film? Which physician, educated partly in Hawaii, led the movement that overthrew the Qing (Manchu) dynasty in 1911? A standard piano has 52 white keys and how many black keys? A picture of which actress, "the Love Goddess", adorned an atomic bomb tested at Bikini Atoll in 1946? What word names a piece of music or a short school essay? What word names a piece of rice or a tiny speck of sand?