Physics Circle home Student Login

Home›Chapters›Moving Charges and Magnetism PYQs›Magnetic Field of Straight Wires›Question 15

MHT CET 2025 (21 Apr, Shift 2) · Magnetic Field of Straight Wires

Magnetic Field of Straight Wires question from MHT CET 2025 (21 Apr, Shift 2)

Q15MHT CET 2025 · 21 APR · SHIFT 2Medium

Magnetic Field of Straight Wires

Two long parallel wires carry currents I1I_1 and I2 (I1>I2)I_2\ (I_1 > I_2). When currents are flowing in the same direction, the magnetic field at a point midway between the wires is 6×10−6 T6 \times 10^{-6}\text{ T}. If the direction of I2I_2 is reversed the field at midpoint becomes 3×10−5 T3 \times 10^{-5}\text{ T}. The ratio I1:I2I_1 : I_2 is

Show answer and solution

Answer: (a)

  1. Same direction: k(I1−I2)=6×10−6k(I_1 - I_2) = 6 \times 10^{-6}; reversed: k(I1+I2)=3×10−5k(I_1 + I_2) = 3 \times 10^{-5}.
  2. I1+I2I1−I2=5⇒4I1=6I2\frac{I_1 + I_2}{I_1 - I_2} = 5 \Rightarrow 4I_1 = 6I_2
  3. I1:I2=3:2I_1 : I_2 = 3 : 2
  4. So the answer is (a) 3:23 : 2.
Report a mistake

More questions on Magnetic Field of Straight Wires