A positive point charge is released from rest at a distance r0 from a… | JEE Main 2019 (8 Apr, Shift 2)

Q52JEE Main 2019 · 8 APR · SHIFT 2Medium

Electrostatic Potential Energy

A positive point charge is released from rest at a distance r0 from a positive line charge with uniform density. The speed (v) of the point charge, as a function of instantaneous distance r from line charge, is proportional to :-

Show answer and solution

Answer: (d)

Field of a line charge: $E = \frac{\lambda}{2\pi\varepsilon_0 r}$ .
Work done by the field from $r_0$ to $r$ : $W = \int_{r_0}^{r} \frac{q\lambda}{2\pi\varepsilon_0 r}dr = \frac{q\lambda}{2\pi\varepsilon_0}\ln\frac{r}{r_0}$
$\frac{1}{2}mv^2 = W \Rightarrow v \propto \sqrt{\ln\left(\frac{r}{r_0}\right)}$
So the answer is (d).

Report a mistake

More questions on Electrostatic Potential Energy

Four equal point charges Q each are placed in the xy plane at (0, 2), (4, 2), (4, –2) and…JEE Main 2019 (10 Jan, Shift 2)
A uniformly charged ring of radius 3a and total charge q is placed in xy-plane centred at…JEE Main 2019 (10 Apr, Shift 1)
There is a uniform spherically symmetric surface charge density at a distance R0 from the…JEE Main 2019 (12 Jan, Shift 1)
Three charges, each +q, are placed at the corners of an isosceles triangle ABC of sides…NEET 2011 (AIPMT, Mains)
Two points P and Q are maintained at the potentials of 10 V and -4 V, respectively. The…JEE Main 2009 (AIEEE)
Charges +q and - q are placed at points A and B respectively which are a distance 2L…NEET 2007 (AIPMT)
As per the diagram a point charge +q is placed at the origin O. Work done in taking…NEET 2005 (AIPMT)
Two charges q1 and q2 are placed 30 cm apart, as shown in the figure. A third charge q3…NEET 2005 (AIPMT)

Electrostatic Potential Energy question from JEE Main 2019 (8 Apr, Shift 2)

More questions on Electrostatic Potential Energy