Question

In the circuit shown below, a current 3 I enters at A. The semicircular parts ABC and ADC have equal radii r but resistances 2R and R respectively. The magnetic field at the center of the circular loop ABCD is ______.

Fill in the blank with the correct answer from the options given below

• A. $\frac{μ_0I}{4r}$ out of the plane
• B. $\frac{μ_0I}{4r}$ into the plane
• C. $\frac{μ_03I}{4r}$ out the plane
• D. $\frac{μ_03I}{4r}$ into the plane

Answer 1

Answer: (D)

$\frac{μ_03I}{4r}$ into the plane

Answer 2

The magnetic field at the center of a loop carrying current is given by $B=\frac{μ0I}{2r}$. The combination of two semicircular currents leads to a net magnetic field proportional to the sum of the currents and inversely proportional to the radius.