HC Verma: Concepts of Physics - Volume 2 Magnetic Field Pages 230-234: Q22 Solution: Two metal strips, each of length , are clamped parallel to each …

QPages 230-234: Q22: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Pages 230-234: Q22 Solution: Two metal strips, each of length , are clamped parallel to each …

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often think the magnetic force changes the normal force and thus the friction. In this setup the magnetic force is horizontal ($mathbf{F}=i,l,mathbf{B}$), so the normal remains $N=m g$ and the kinetic friction is $mu N=mu m g$. Using the right‑hand rule to confirm the direction of $mathbf{F}$ and remembering that friction opposes motion avoids the error.

Two metal strips, each of length

l

, are clamped parallel to each other on a horizontal floor with a separation

b

between them. A wire of mass

m

lies on them perpendicularly, as shown in the figure. A vertically-upward magnetic field of strength

B

exists in the space. The metal strips are smooth but the coefficient of friction between the wire and the floor is

\mu

. A current

i

is established when the switch S is closed at the instant

t = 0

. Discuss the motion of the wire after the switch is closed. How far away from the strips will the wire reach?

Step-by-Step Verified Solution

**Answer:** The wire moves with acceleration

a = i l B/m - \mu g

. **Step-by-Step Explanation:** When switch S is closed, current flows. The magnetic force

F = i l B

acts horizontally. Friction

f = \mu m g

opposes motion. The net acceleration is

a = (i l B - \mu m g)/m

QPages 230-234: Q22: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Pages 230-234: Q22 Solution: Two metal strips, each of length , are clamped parallel to each …

Step-by-Step Verified Solution

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