JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
A square loop is carrying a steady current \(I\) and the magnitude of its magnetic dipole moment is \(m\). If this square loop is changed to a circular loop and it carries the same current, the magnitude of the magnetic dipole moment of circular loop will be
- A \(\frac {m}{\pi }\)
- B \(\frac {3m}{\pi }\)
- C \(\frac {4m}{\pi }\)
- D \(\frac {2m}{\pi }\)
Answer & Solution
Correct Answer
(C) \(\frac {4m}{\pi }\)
Step-by-step Solution
Detailed explanation
\(m = I{l^2}\) \(2\pi r = 4l\) \({{{\text{m}}^\prime } = \frac{{I4{\ell ^2}}}{\pi }}\) \({{\text{r}} = \frac{{2\ell }}{\pi }}\) \({{{\text{m}}^\prime } = \frac{{I4{\ell ^2}}}{\pi }}\) \({\pi {r^2} = \frac{{\pi 4{\ell ^2}}}{{{\pi ^2}}} = \frac{{4{\ell ^2}}}{\pi }}\)…
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 cube of ice floats partly in water and partly in kerosene oil. The ratio of volume of ice immersed in water to that in kerosene oil is _______.(specific gravity of Kerosene oil \(=0.8\), specific gravity of ice \(=0.9\) )
JEE Mains 2024 Hard - An electron revolves around an infinite cylindrical wire having uniform linear change density \(2 \times 10^{-8}\,Cm ^{-1}\) in circular path under the influence of attractive electrostatic field as shown in the figure. The velocity of electron with which it is revolving is \(.........\times 10^6\,ms ^{-1}\). Given mass of electron \(=9 \times 10^{-31}\,kg\)
JEE Mains 2023 Medium - A particle of mass \(m\) is moving with speed \(2\, v\) collides with a mass \(2\,m\) moving with speed \(v\) in the same direction. After collision, the first mass is stopped completely while the second one splits into two particles each of mass \(m\), which move at angle \(45^o\) with respect to the original direction. The speed of each of the moving particle will beJEE Mains 2019 Medium
- Assume there are two identical simple pendulum Clocks\(-1\) is placed on the earth and Clock\(-2\) is placed on a space station located at a height \(h\) above the earth surface. Clock\(-1\) and Clock\(-2\) operate at time periods \(4\,s\) and \(6\,s\) respectively. Then the value of \(h\) is \(....km\) (consider radius of earth \(R _{ E }=6400\,km\) and \(g\) on earth \(10\,m / s ^{2}\) )JEE Mains 2022 Hard
- Match List\(-I\) with List\(-II\)
Question: Choose the correct answer from the options given belowList \(-I\) List \(-II\) \((A)\) Moment of inertia of solid sphere of radius \((R)\) about any tangent \((I)\) \(\frac{5}{3} MR ^{2}\) \((B)\) Moment of inertia of hollow sphere of radius \((R)\) about any tangent \((II)\) \(\frac{7}{5} MR ^{2}\) \((C)\) Moment of inertia of circular ring of radius \((R)\) about its diameter. \((III)\) \(\frac{1}{4} MR ^{2}\) \((D)\) Moment of inertia of circular disc of radius \((R)\) about any diameter. \((IV)\) \(\frac{1}{2} MR ^{2}\) JEE Mains 2022 Medium - Statement\(-I :\) By doping silicon semiconductor with pentavalent material, the electrons density increases. Statement\(-II :\) The \(n-\)type semiconductor has net negative charge. In the light of the above statements, choose the most appropriate answer from the options given below:JEE Mains 2021 Medium
More PYQs from JEE Mains
- Let \(10\) vertical poles standing at equal distances on a straight line, subtend the same angle of elevation at a point \(O\) on this line and all the poles are on the same side of \(O\). If the height of the longest pole is \('h'\) and the distance of the foot of the smallest pole from \(O\) is \('a'\); then the distance between two consecutive poles, isJEE Mains 2015 Hard
- Let \(\overrightarrow{\mathrm{a}}=2 \hat{\mathrm{i}}+\hat{\mathrm{j}}-\hat{\mathrm{k}}, \overrightarrow{\mathrm{b}}=((\overrightarrow{\mathrm{a}} \times(\hat{\mathrm{i}}+\hat{\mathrm{j}})) \times \hat{\mathrm{i}}) \times \hat{\mathrm{i}}\). Then the square of the projection of \(\vec{a}\) on \(\vec{b}\) is :JEE Mains 2024 Hard
- A thin glass plate of thickness is \(\frac{{2500}}{3}\,\lambda \) (\(\lambda \) is wavelength of light used) and refractive index \(\mu = 1.5\) is inserted between one of the slits and the screen in Young's double slit experiment. At a point on the screen equidistant from the slits, the ratio of the intensities before and after the introduction of the glass plate isJEE Mains 2013 Hard
- A dipole with two electric charges of \(2 \mu \mathrm{C}\) magnitude each, with separation distance \(0.5 \mu \mathrm{~m}\), is placed between the plates of a capacitor such that its axis is parallel to an electric field established between the plates when a potential difference of 5 V is applied. Separation between the plates is 0.5 mm. If the dipole is rotated by \(30^{\circ}\) from the axis, it tends to realign in the direction due to a torque. The value of torque is :JEE Mains 2025 Medium
- The current in a coil of self inductance \(2.0 \,H\) is increasing according to \(I =2 \sin \left( t ^{2}\right) A\). The amount of energy spent during the period when current changes from \(0\) to \(2\, A\) is......\(J.\)JEE Mains 2022 Medium
- From the base of a pole of height \(20\) meter, the angle of elevation of the top of a tower is \(60^{\circ}\). The pole subtends an angle \(30^{\circ}\) at the top of the tower. Then the height of the tower isJEE Mains 2022 Medium