JEE Mains · Physics · STD 11 - System of particles and rotational motion
- JEE Mains 2023
- Medium
- Numerical
Solid sphere \(A\) is rotating about an axis \(PQ\). If the radius of the sphere is \(5\,cm\) then its radius of gyration about \(P Q\) will be \(\sqrt{x} \;cm\). The value of \(x\) is \(................\).

Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(110\)
Step-by-step Solution
Detailed explanation
\(I _{ cm }=\frac{2}{5} MR ^2\)
\(I _{ PQ }= I _{ cm }+ md ^2\)
\(I _{ PQ }=\frac{2}{5} mR ^2+ m (10\,cm )^2\)
For radius of gyration
\(I _{ PQ }= mk ^2\)
\(k ^2=\frac{2}{5} R ^2+(10\,cm )^2\)
\(=\frac{2}{5}(5)^2+100\)
\(=10+100=110\)
\(k =\sqrt{110}\,cm\)
\(x =110\)
More questions from Physics
- A convex lens of focal length \(20\,cm\) is placed in front of convex mirror with principal axis coinciding each other. The distance between the lens and mirror is \(10\,cm\). A point object is placed on principal axis at a distance of \(60\,cm\) from the convex lens. The image formed by combination coincides the object itself. The focal length of the convex mirror is \(...cm\).JEE Mains 2022 Medium
- A conducting circular loop is rotated about its diameter at a constant angular speed of 100 rad/s in a magnetic field of 0.5 T perpendicular to the axis of rotation. When the loop is rotated by 30° from the horizontal position, the induced EMF is 15.4 mV. The radius of the loop is ________ mm. (Take \( \pi=22/7 \))JEE Mains 2026 Easy
- A light wave travelling linearly in a medium of dielectric constant \(4,\) incident on the horizontal interface separating medium with air. The angle of incidence for which the total intensity of incident wave will be reflected back into the same medium will be (Given : relative permeability of medium \(\mu_{ s }=1)\)JEE Mains 2022 Hard
- Three charges \(Q, +q\) and \(+q\) are placed at the vertices of a right -angle isosceles triangle as shown below. The net electrostatic energy of the configuration is zero, if the value of \(Q\) is
JEE Mains 2019 Hard - Two beams, \(A\) and \(B\), of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid. From the position when the beam \(A\) has maximum intensity ( and beam \(B\) has zero intensity), a rotation of polaroid through \(30 ^o \) makes the two beams appear equally bright. If the initial intensities of the two beams are \(I_A\) and \(I_B\) respectively, then \(\frac{{{I_A}}}{{{I_B}}}\)=JEE Mains 2014 Medium
- A square shaped hole of side \(l=\frac{a}{2}\) is carved out at a distance \(d =\frac{ a }{2}\) from the centre \('O'\) of a uniform circular disk of radius \(a\). If the distance of the centre of mass of the remaining portion from \(O\) is \(-\frac{a}{X},\) value of \(X\) (to the nearest integer) is.......
JEE Mains 2020 Hard
More PYQs from JEE Mains
- A fly wheel is accelerated uniformly from rest and rotates through \(5 \,rad\) in the first second. The angle rotated by the fly wheel in the next second, will be.........\(rad\)JEE Mains 2022 Easy
- \({ }_{92}^{238} A \rightarrow{ }_{90}^{234} B +{ }_2^4 D + Q\) In the given nuclear reaction, the approximate amount of energy released will be \(.....\,MeV\) \(\text { [Given, mass of }{ }_{92}^{238} A =238.05079 \times 931.5\,MeV / c ^2\) \(\text { mass of }{ }_{90}^{234} B =234.04363 \times 931.5\,MeV / c ^2\) \(\text { mass of } \left.{ }_2^4 D =4.00260 \times 931.5\,MeV / c ^2\right]\)JEE Mains 2023 Easy
- Proton with kinetic energy of \(1\;MeV\) moves from south to north. It gets an acceleration of \(10^{12}\; \mathrm{m} / \mathrm{s}^{2}\) by an applied magnetic field (west to east). The value of magnetic field :.......\(mT\) (Rest mass of proton is \(1.6 \times 10^{-27} \;\mathrm{kg}\) )JEE Mains 2020 Medium
- Match List\(-I\) with List\(-II\).
Choose the most appropriate answer from the options given below:List\(-I\) List\(-II\) \((a)\) \({R}_{{H}}\) (Rydberg constant) \((i)\) \({kg} {m}^{-1} {s}^{-1}\) \((b)\) \(h\) (Planck's constant) \((ii)\) \({kg} {m}^{2} {s}^{-1}\) \((c)\) \(\mu_{{B}}\) (Magnetic field energy density) \((iii)\) \({m}^{-1}\) \((d)\) \(\eta\) (coefficient of viscocity) \((iv)\) \({kg} {m}^{-1} {s}^{-2}\) JEE Mains 2021 Hard - A particle is placed at the point \(\mathrm{A}\) of a frictionless track \(A B C\) as shown in figure. It is gently pushed toward right. The speed of the particle when it reaches the point \(B\) is _______. \(\left(\right.\) Take \(g=10 \mathrm{~m} / \mathrm{s}^2\) ).
JEE Mains 2024 Hard - From a solid sphere of mass \(M\) and radius \(R\) a cube of maximum possible volume is cut. Moment of inertia of cube about an axis passing through its center and perpendicular to one of its faces isJEE Mains 2015 Hard