If coil is opened, then L and R become

Options

A. `oo,0`
B. `0,oo`
C. `oo,oo`
D. `0,0`

Answer

B

Explanation

When coil is open, there is no current in it, hence no flux is associated with it, i.e. `phi=0`. Also, we know that flux linked with the coil is directly proportional to the current in the coil, i.e. `phipropi`
or `phi=Li`
where L is proportionally constant known as self-inductance
`thereforeL=(phi)/(i)=0`
Again since `i=0`, hence `R=oo`