Question

Four identical long solenoids $A,B,C$ and $D$ are connected to each other as shown in the figure. If the magnetic field at the center of $A$ is $3\text{T}$, the field at the center of $C$ would be: (Assume that the magnetic field is confined within the volume of respective solenoid.)

• A. $6\text{T}$
• B. $12\text{T}$
• C. $1\text{T}$
• D. $9\text{T}$

Answer 1

The correct option is C $1\text{T}$

Since they are identical solenoid, current will divide equally.

We know that, magnetic field due to solenoid at its centre $B\propto i$
So, field at centre of $C=3\times \frac{i_0/3}{i_0}=1\text{T}$