Electrical resistance of certain materials , known as superconductors , changes abruptly from a nonzero value to zero as their temperature is lowered below a critical temperature
. An interesting property of superconductors is that their critical temperature becomes smaller than
if they are placed in a magnetic field, i.e., the critical temperature
is functional of the magnetic field strength B. the dependence of
(B) on B is shown in the figure.
In the graphs below, the resistance R of a superconductor is shown as a function of its temperature T for two different magnetic fields
(solid line) and
(dashed line). if
is larger than
, which of the following graphs shows the correct variation of R with T in these fields ?