JEE Main 2021 · PhysicsNumerical answerNumerical valueHardMulti-step

JEE Main 4 August 2021, Shift 1, Physics Q23

Question 23 of 90 in this shift, Physics question 23 of 30, Section B.

A drop of liquid of mass

1.8 \times 10^{-5}

kg falls away from the bottom of a charged conducting sphere of radius 20 cm, carrying with it a charge of 1nC and leaving on the sphere a uniformly distributed charge of 2.5

\mu

C. The speed of the drop, after it has fallen 30 cm is

\sqrt{\frac{x^3}{2}}

m/s. The value of x will be ________. (g = 10 m/s

^2

)

Official answer

NTA final key.

Chapter: Electrostatic Potential and Capacitance
Topic: Electric Potential
Idea tested: Work Done in Field

Same idea in other shifts

Asked 4× in all

7 Apr 2025, Shift 1 · Q38Two charges $q_1$ and $q_2$ are separated by a distance of 30 cm. A third charge $q_3$ initially at 'C' as shown in the figure, is moved…MediumDiagram basedHas a figure
26 Feb 2021, Shift 1 · Q27In an electrical circuit, a battery is connected to pass 20 C of charge through it in a certain given time. The potential difference…EasyNumerical value
4 Sep 2020, Shift 1 · Q11A two point charges 4q and $-$ q are fixed on the $x$ -axis at $x=-\frac{d}{2}$ and $x=\frac{d}{2}$ , respectively. If a third point charge…MediumDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.