Let us consider a copper wire having radius r and length l. Let its resistance be R. If the radius of another copper wire is 2r and the length is l/2, then the resistance of this wire will be

Basic scientific principle behind a nuclear reactor is

Who among the following has explained the phenomenon of photoelectric effect?

Two metallic wires A and B are made using copper. The radius of wire A is r while its length is l. A DC voltage V is applied across the wire A, causing power dissipation P. The radius of wire B is 2r and its length is 2l and the same DC voltage V is applied across it causing power dissipation P₁. Which one of the following is the correct relationship between P and P₁ ?