Misc: Which composer wrote a work for instrumentalists and short wave radios?

Questions

Which civil rights leader was killed by James earl ray in 1968?

Which oil bearing substance did Noah use to coat the Ark and make it waterproof?

Which italian scientist is said to have dropped cannon balls from a tower to study how they fell to earth?

Caliph Harun al-Rashid of Baghdad featured in which series of eastern stories?

What is the most famous church designed by Sir Christopher Wren?