question_answer

A uniform magnetic field is restricted within a region of radius r. The magnetic field changes with time at a rate\[\frac{d\overset{\to }{\mathop{B}}\,}{dt}\]. Loop 1 of radius \[R>r\] encloses the region r and loop 2 of radius R is outside the region of magnetic field as shown in the figure below. Then the e.m.f. generated is

A)  Zero in loop 1 and zero in loop 2

B)  \[-\frac{d\overset{\to }{\mathop{B}}\,}{dt}\pi {{r}^{2}}\text{in loop 1 and}\,-\frac{d\overset{\to }{\mathop{B}}\,}{dt}\pi {{r}^{2}}\,\text{in}\,\text{loop}\,\text{2}\]

C)  \[-\frac{d\overset{\to }{\mathop{B}}\,}{dt}\pi {{r}^{2}}\text{in loop 1 and zero in loop 2}\]

D)  \[~-\frac{d\overset{\to }{\mathop{B}}\,}{dt}\pi {{r}^{2}}\text{in loop 1 and zero in loop 2}\]