JEE Main 2022 · 27 Jul · Shift 2 · Physics Q36

← JEE Main 2022 · 27 Jul · Shift 2

PhysicsSingle correct+4 / -1Question 36 of 90

A body of mass m is projected with velocity $\lambda v_e$ in vertically upward direction from the surface of the earth into space. It is given that $v_e$ is escape velocity and $\lambda<1$ . If air resistance is considered to be negligible, then the maximum height from the centre of earth, to which the body can go, will be :

(R : radius of earth)

\dfrac R{1+\lambda^2}

\dfrac R{1-\lambda^2}

\dfrac R{1-\lambda}

\dfrac{\lambda^2R}{1-\lambda^2}

Answer and worked solution

Official answer: B

Energy. $\frac12\lambda^2v_e^2=GM\left(\frac1R-\frac1r\right)$ with $v_e^2=\frac{2GM}R$ gives $r=\frac R{1-\lambda^2}$ .

(B)

Topics:Escape velocity Gravitational field and potential

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JEE Main 2022 · 27 Jul · Shift 2, Physics question 36