The surface area sr (in square meters) of a spherical balloon with radius r meters is given by =sr4πr2. the radius pt (in meters) after t seconds is given by =pt73t. write a formula for the surface area nt (in square meters) of the balloon after t seconds. it is not necessary to simplify.

The magnitude of the magnetic field at a certain distance from a long, straight conductor is represented by b. what is the magnitude of the magnetic field at twice the distance from the conductor? a. at twice the distance, the magnitude of the field is 4b.b. at twice the distance, the magnitude of the field is 2b.c. at twice the distance, the magnitude of the field is b/2.d. at twice the distance, the magnitude of the field is b/4.e. at twice the distance, the magnitude of the field remains equal to b.