JEE PHYSICS MCQ: ELECTRIC FIELDS AND CHARGES

1 Medium

1 of 1

Analyzing +4 | -1

A soap bubble of radius

R

has uniformly distributed charge

Q

on it's surface. It's energy is the self-energy of charges & surface energy due to surface tension. In equilibrium, this energy is minimum. Surface tension is

\mathrm{S}

. At equilibrium radius of bubble is R & pressure inside is

\mathrm{P}

. Pressure outside is

\mathrm{P}_0

. Then

View answer and explanation

Correct option: A

R=\left(\frac{Q^2}{128 \pi^2 \in_0 S}\right)^{1 / 3}

Option A (

R=\left(\frac{{Q^2}}{{128 \pi^2 \in_0 S}}\right)^{1 / 3}

) is correct because it represents the equilibrium radius derived from minimizing the total energy of the bubble.

More Questions from ELECTRIC FIELDS AND CHARGES

Practice All Chapter MCQs →

Assertion:- Electric field lines do not cut at any point.
Reason:- At any point, there is only one direction of electric field. Statement-I: A positive point charge is brought in an electric field, the electric field at neary by point will increase

Statement-II: Electric field produced by charge may favour the existing electric filed Two particles having equal mass and charge
are separated by a distance

r.

The force(s) they
experience is (are) Statement-I: No 2 electric lines of force can intersect each other

Statement-II: tangent at any point of electric line of force gives the direction of electric field A force of

4N

is acting between two charges in air if the space between them is completely filled with glass

\left( {{\varepsilon _r} = 8} \right)

, then the new force will be ……

N

An electron is placed at centre of a conducting sphere of radius 0.2 metre having charge

5 \times {10^{ - 2}}

coulomb. The force of on the electron is ________ N