JEE Advanced · Physics · 20. Magnetism & Current
A thin flexible wire of length \(L\) is connected to two adjacent fixed points and carries a current \(I\) in the clockwise direction, as shown in the figure. When the system is put in a uniform magnetic field of strength \(B\) going into the plane of the paper, the wire takes the shape of a circle. The tension in the wire is
- A \(I B L\)
- B \(\frac{I B L}{\pi}\)
- C \(\frac{I B L}{2 \pi}\)
- D \(\frac{I B L}{4 \pi}\)
Answer & Solution
Correct Answer
(C) \(\frac{I B L}{2 \pi}\)
Step-by-step Solution
Detailed explanation
\(L=2 \pi R\)
\(R=\frac{L}{2 \pi}\)
\(2 T \sin (d \theta)=F_m\)
for small angles, \(\sin (d \theta) \approx d \theta\)
\(\begin{aligned}
\therefore 2 T(d \theta) & =I(d L) B \sin 90^{\circ} \\
& =I(2 R \cdot d \theta) \cdot B \\
\therefore T & =I R B=\frac{I L B}{2 \pi}
\end{aligned}\)
\(\therefore\) correct option is (c)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- A ball is projected from the ground at an angle of with the horizontal surface. It reaches a maximum height of and returns to the ground. Upon hitting the ground for the first time, it loses half of its kinetic energy. Immediately after the bounce, the velocity of the ball makes an angle of with the horizontal surface. The maximum height it reaches after the bounce (in meters) is _____________.JEE Advanced 2018 Medium
- One mole of an ideal gas in initial state A undergoes a cyclic process \(A B C A\), as shown in the figure. Its pressure at \(A\) is \(p_0\). Choose the correct option(s) from the following
JEE Advanced 2010 Medium - A rod of length makes an angle with the principal axis of a thin convex lens. The lens has a focal length of and is placed at a distance of from the object as shown in the figure. The height of the image is and the angle made by it with respect to the principal axis is \(\alpha\) rad. The value of is , where is
JEE Advanced 2022 Hard - An infinitely long wire, located on the \(z\)-axis, carries a current \(I\) along the \(+z\)-direction and produces the magnetic field \(\vec{B}\). The magnitude of the line integral \(\int \vec{B} \cdot \overrightarrow{d l}\) along a straight line from the point \((-\sqrt{3} a, a, 0)\) to \((a, a, 0)\) is given by
[ \(\mu_0\) is the magnetic permeability of free space.]JEE Advanced 2024 Hard - The activity of a freshly prepared radioactive sample is \(10^{10}\) disintegrations per second, whose mean life is \(10^{-9} \mathrm{~s}\). The mass of an atom of this radioisotope is \(10^{-25} \mathrm{~kg}\). The mass (in \(\mathrm{mg}\) ) of the radioactive sample isJEE Advanced 2011 Medium
- An electric dipole is formed by two charges and located in -plane at and , respectively, as shown in the figure. The electric potential at point due to the dipole is . The charges and are then moved to the points and , respectively. What is the value of electric potential atJEE Advanced 2023 Medium
More PYQs from JEE Advanced
- Silver (atomic weight \(=108 \mathrm{~g} \mathrm{~mol}^{-1}\) ) has a density of \(10.5 \mathrm{~g} \mathrm{~cm}^{-3}\). The number of silver atoms on a surface of area \(10^{-12} \mathrm{~m}^2\) can be expressed in scientific notation as \(y \times 10^x\). The value of \(x\) isJEE Advanced 2010 Easy
- Let be a triangle. Let If and then which of the following is (are) true ?JEE Advanced 2015 Medium
- For a > b > c > 0, the distance between (1, 1) and the point of intersection of the lines ax + by + c = 0 and bx + ay + c = 0 is less than .ThenJEE Advanced 2013 Medium
- A water cooler of storage capacity 120 litres can cool water at constant rate of P watts. In a closed circulation system (as shown schematically in the figure), the water from the cooler is used to cool an external device that generates constantly 3 kW of heat (thermal load). The temperature of water fed into the device cannot exceed and the entire stored 120 litres of water is initially cooled to . The entire system is thermally insulated. The minimum value of P (in watts) for which the device can be operated for 3 hours is:
(Specific heat of water is 4.2 kJ and the density of water is 1000 kg )JEE Advanced 2016 Hard - Two concentric circular loops, one of radius and the other of radius , lie in the -plane with the origin as their common center, as shown in the figure. The smaller loop carries current in the anti-clockwise direction and the larger loop carries current in the clockwise direction, with denotes the magnetic field at a point in the -plane. Which of the following statement(s) is (are) correct?
JEE Advanced 2021 Hard - The total number of distinct for which, isJEE Advanced 2016 Hard