GK: Why is the sound on the radio more clear after sunset? Click here to know

GK: Why is the sound on the radio more clear after sunset? Click here to know

Question 1: Due to which the sound is heard more clearly on the radio after sunset? 
Answer: Due to the increase in the density of the ionosphere
Question 2: Which is called the city of seven islands?
Answer: Mumbai

Question 3: When is the Central Reserve Police Day celebrated?
Answer: 28 December 
Question 4: Who published the first book in the world?
Answer: Coaster 

Question 5: In which country cloth newspaper is printed?
Answer: Spain