A. Some materials exhibit the property of superconductivity under certain conditions. State what is meant by superconductivity and explain the required conditions for the
material to become superconducting.

Conditions for Superconductivity

The material must be cooled below a characteristic temperature, known as its superconducting transition or critical temperature (Tc). ... The magnetic field to which the material is exposed must be below a characteristic value known as the critical magnetic field (Hc).

the answer is b

explanation:

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.