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Four identical wires of length L each ar...

Four identical wires of length L each are bent into four different planar figures: an equilateral triangle, a square, a regular hexagon and a circle. The loops are kept far away from each other and made to carry equal current I. The magnetic field intensity at the centre of the figures are recorded as `B_(T),B_(S),B_(H)` and `B_(C)`. Choose the correct option(s):

A

`B_(T)=(27mu_(0)I)/(2piL)`

B

`B_(H)=(6 sqrt(3)mu_(0)I)/(piL)`

C

`B_(S)=(8sqrt(2)mu_(0)I)/(piL)`

D

`B_(T)gtB_(S)gtB_(H)gtB_(C)`

Text Solution

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To solve the problem, we need to calculate the magnetic field intensity at the center of each of the four shapes formed by bending the wires: an equilateral triangle, a square, a regular hexagon, and a circle. ### Step-by-step Solution: 1. **Identify the Length of Each Side:** Each wire has a total length \( L \). For each shape, we need to determine the length of each side: - **Equilateral Triangle:** Each side \( = \frac{L}{3} \) - **Square:** Each side \( = \frac{L}{4} \) - **Regular Hexagon:** Each side \( = \frac{L}{6} \) - **Circle:** The circumference \( = L \), so the radius \( R = \frac{L}{2\pi} \) 2. **Calculate the Magnetic Field for Each Shape:** The magnetic field \( B \) at the center of a loop carrying current \( I \) is given by the formula: \[ B = \frac{\mu_0 I}{4\pi R} \cdot \text{(sum of contributions from each segment)} \] - **For the Equilateral Triangle:** Each segment contributes equally. The distance from the center to each side is \( \frac{L}{6\sqrt{3}} \). The angle subtended by each side at the center is \( 60^\circ \). \[ B_T = \frac{3 \cdot \mu_0 I}{4\pi \left(\frac{L}{6\sqrt{3}}\right)} \cdot \sin(60^\circ) = \frac{27 \mu_0 I}{2\pi L} \] - **For the Square:** Each side contributes equally. The distance from the center to each side is \( \frac{L}{8} \). The angle subtended by each side at the center is \( 90^\circ \). \[ B_S = \frac{4 \cdot \mu_0 I}{4\pi \left(\frac{L}{8}\right)} \cdot \sin(45^\circ) = \frac{8\sqrt{2} \mu_0 I}{\pi L} \] - **For the Regular Hexagon:** Each side contributes equally. The distance from the center to each side is \( \frac{L}{12} \). The angle subtended by each side at the center is \( 60^\circ \). \[ B_H = \frac{6 \cdot \mu_0 I}{4\pi \left(\frac{L}{12}\right)} \cdot \sin(30^\circ) = \frac{6\sqrt{3} \mu_0 I}{\pi L} \] - **For the Circle:** The magnetic field at the center of a circular loop is given by: \[ B_C = \frac{\mu_0 I}{2R} = \frac{\mu_0 I}{2 \cdot \frac{L}{2\pi}} = \frac{\mu_0 I \pi}{L} \] 3. **Comparing the Magnetic Fields:** Now we compare the magnitudes of the magnetic fields: - \( B_T = \frac{27 \mu_0 I}{2\pi L} \) - \( B_S = \frac{8\sqrt{2} \mu_0 I}{\pi L} \) - \( B_H = \frac{6\sqrt{3} \mu_0 I}{\pi L} \) - \( B_C = \frac{\mu_0 I \pi}{L} \) ### Conclusion: After calculating the magnetic fields, we can rank them based on their values: - \( B_T > B_S > B_H > B_C \)

To solve the problem, we need to calculate the magnetic field intensity at the center of each of the four shapes formed by bending the wires: an equilateral triangle, a square, a regular hexagon, and a circle. ### Step-by-step Solution: 1. **Identify the Length of Each Side:** Each wire has a total length \( L \). For each shape, we need to determine the length of each side: - **Equilateral Triangle:** Each side \( = \frac{L}{3} \) - **Square:** Each side \( = \frac{L}{4} \) ...
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