JEE Mains · Physics · STD 11 - Gravitation
- JEE Mains 2025
- Easy
- MCQ
Given below are two statements: one is labelled as Assertion \(\mathrm{A}\) and the other is labelled as Reason \(\mathrm{R}\) Assertion A : The kinetic energy needed to project a body of mass m from earth surface to infinity is \(\frac{1}{2} \mathrm{mgR}\), where R is the radius of earth.
Reason \(\mathrm{R}\) : The maximum potential energy of a body is zero when it is projected to infinity from earth surface.
In the light of the above statements, choose the correct answer from the option given below
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(\mathrm{A}\) False but \(\mathrm{R}\) is true
Step-by-step Solution
Detailed explanation
\(\mathrm{KE}=\frac{1}{2} \mathrm{~m}\left(\frac{2 \mathrm{Gm}}{\mathrm{R}}\right)=\mathrm{mgR}\)
Assertion wrong
at \(\infty\)
\(\mathrm{U}=0\)
\(\therefore\) Reason correct.
Assertion wrong
at \(\infty\)
\(\mathrm{U}=0\)
\(\therefore\) Reason correct.
More questions from Physics
- Three concentric metal shells \(A, B\) and \(C\) of respective radii \(a, b\) and \(c (a < b < c)\) have surface charge densities \(+\sigma,-\sigma\) and \(+\sigma\) respectively. The potential of shell \(B\) isJEE Mains 2018 Hard
- Two water drops each of radius 'r' coalesce to from a bigger drop. If ' T ' is the surface tension, the surface energy released in this process is :JEE Mains 2025 Easy
- A convex lens made of glass (refractive index \(=1.5\) ) has focal length 24 cm in air. When it is totally immersed in water (refractive index \(=1.33\) ), its focal length changes to ________.JEE Mains 2025 Medium
- One main scale division of a vernier callipers is \(a\) \(cm\) and \(n ^{\text {th }}\) division of the vernier scale coincide with \(( n -1)^{\text {th }}\) division of the main scale. The least count of the callipers in \(mm\) isJEE Mains 2021 Medium
- Two electrons each are fixed at a distance \('2d'\). A third charge proton placed at the midpoint is displaced slightly by a distance \(x ( x << d )\) perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency : \(( m =\) mass of charged particle)JEE Mains 2021 Hard
- The magnetic field of a plane electromagnetic wave is given by \(\overrightarrow{ B }=2 \times 10^{-8} \sin \left(0.5 \times 10^{3} x +1.5 \times 10^{11} t \right) \hat{ j } T\) The amplitude of the electric field would be.JEE Mains 2022 Medium
More PYQs from JEE Mains
- One mole of an ideal gas at \(27^{\circ} {C}\) is taken from \({A}\) to \({B}\) as shown in the given \({PV}\) indicator diagram. The work done by the system will be \(......\times 10^{-1} \,{J}\) [Given : \(R=8.3\, {J} /\,mole\,{K}, \ln 2=0.6931\) ] (Round off to the nearest integer)
JEE Mains 2021 Medium - The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiationJEE Mains 2021 Easy
- Two loudspeakers ( \(L_1\) and \(L_2\) ) are placed with a separation of 10 m , as shown in figure. Both speakers are fed with an audio input signal of same frequency with constant volume. A voice recorder, initially at point \(A\), at equidistance to both loud speakers, is moved by 25 m along the line \(A B\) while monitoring the audio signal. The measured signal was found to undergo 10 cycles of minima and maxima during the movement. The frequency of the input signal is __________ Hz
(Speed of sound in air is \(324 m / s\) and \(\sqrt{5}=2.23\) )
JEE Mains 2026 Hard