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NEET PHYSICSMOVING CHARGES AND MAGNETISMEasy

Question

Two very long, straight, parallel conductors A and B carry current of 5 A and 10 A respectively and are at a distance of 10 cm from each other. The direction of the current in the two conductors is the same. The force acting per unit length between two conductors is: (μ0=4π×10−7\mu_0=4\pi \times 10^{-7} SI unit)

A

2×10−4 N m−12\times 10^{-4} \text{ N m}^{-1} and is attractive

B

2×10−4 N m−12\times 10^{-4} \text{ N m}^{-1} and is repulsive

C

1×10−4 N m−11\times 10^{-4} \text{ N m}^{-1} and is attractive

D

1×10−4 N m−11\times 10^{-4} \text{ N m}^{-1} and is repulsive

Step-by-Step Solution

  1. Identify Formula: The magnetic force per unit length (F/lF/l) between two infinite parallel current-carrying conductors is given by: Fl=μ0I1I22πd\frac{F}{l} = \frac{\mu_0 I_1 I_2}{2\pi d} where I1I_1 and I2I_2 are the currents and dd is the separation distance.
  2. Substitute Values: I1=5 AI_1 = 5 \text{ A} I2=10 AI_2 = 10 \text{ A} d=10 cm=0.1 md = 10 \text{ cm} = 0.1 \text{ m} μ0=4π×10−7 T m/A\mu_0 = 4\pi \times 10^{-7} \text{ T m/A} Fl=(4π×10−7)×5×102π×0.1\frac{F}{l} = \frac{(4\pi \times 10^{-7}) \times 5 \times 10}{2\pi \times 0.1}
  3. Calculate Magnitude: Fl=2×10−7×500.1=100×10−70.1=10−510−1=10−4 N m−1\frac{F}{l} = \frac{2 \times 10^{-7} \times 50}{0.1} = \frac{100 \times 10^{-7}}{0.1} = \frac{10^{-5}}{10^{-1}} = 10^{-4} \text{ N m}^{-1}
  4. Determine Direction:
  • Currents flowing in the same direction attract each other.
  • Currents flowing in opposite directions repel each other.
  • Since the problem states the direction is the same, the force is attractive.
  1. Conclusion: The force is 1×10−4 N m−11 \times 10^{-4} \text{ N m}^{-1} and is attractive.

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from MOVING CHARGES AND MAGNETISM. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSMOVING CHARGES AND MAGNETISMstraightparallelconductorscurrentrespectively

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