When the distance between two charges I no halved, the electric force between the charges A) quadruples
B) doubles
C) is half
D) is reduced by one quarter

A)quadruples

Explanation:

The force between the two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Hence, if distance between charges is halved (charges remaining kept constant), the force between the two charges is quadrupled

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.