HC Verma: Concepts of Physics - Volume 2 Magnetic Field Due to a Current Pages 249-253: Q12 Solution: Four long, straight wires, each carrying a current of 5.0 A,…

QPages 249-253: Q12: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Due to a Current Pages 249-253: Q12 Solution: Four long, straight wires, each carrying a current of 5.0 A,…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students frequently sum the magnitudes of the four wire fields at the centre or diagonal points, ignoring the direction given by the right‑hand rule; the magnetic field from each straight wire is tangent to a circle centred on the wire, so at the centre the contributions are opposite and cancel, while at Q1 and Q3 the geometry yields a net vector that does not cancel. Always resolve each wire's field into components before adding.

Four long, straight wires, each carrying a current of 5.0 A, are placed in a plane as shown in figure. The points of intersection form a square of side 5.0 cm. a) Find the magnetic field at the centre

P

of the square. b)

Q_1, Q_2, Q_3

, and

Q_4

, are points situated on the diagonals of the square and at a distance from P that is equal to the diagonal of the square. Find the magnetic fields at these points.

Step-by-Step Verified Solution

**Answer:** (a) 0 (b)

B_{Q1} = 1.1 \times 10^{-4}

T (c)

B_{Q2} = 0

(d)

B_{Q3} = 1.1 \times 10^{-4}

T (e)

B_{Q4} = 0

. **Step-by-Step Explanation:** Four wires at corners of a square of side 5 cm, 5 A each. At centre P: fields cancel,

B = 0

. At Q1 (on diagonal, distance = diagonal):

B = 1.1 \times 10^{-4}

T. At Q2:

B = 0

. At Q3:

B = 1.1 \times 10^{-4}

T (downward). At Q4:

B = 0

QPages 249-253: Q12: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Due to a Current Pages 249-253: Q12 Solution: Four long, straight wires, each carrying a current of 5.0 A,…

Step-by-Step Verified Solution

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