Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Electrostatics question

2003 · Shift 0 · Q167
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Electrostatics
  5. /2003 · Shift 0 · Q167

Electrostatics question

2003 · Shift 0 · Q167

JEE MainPhysicsElectrostaticsMCQ+4 / −1
If the electric flux entering and leaving an enclosed surface respectively is ϕ1{\phi _1}ϕ1​ and ϕ2,{\phi _2},ϕ2​, the electric charge inside the surface will be
  1. A
    (ϕ2−ϕ1)ε0\left( {{\phi _2} - {\phi _1}} \right){\varepsilon _0}(ϕ2​−ϕ1​)ε0​
  2. B
    (ϕ2+ϕ1)/ε0\left( {{\phi _2} + {\phi _1}} \right)/{\varepsilon _0}(ϕ2​+ϕ1​)/ε0​
  3. C
    (ϕ1−ϕ2)/ε0\left( {{\phi _1} - {\phi _2}} \right)/{\varepsilon _0}(ϕ1​−ϕ2​)/ε0​
  4. D
    (ϕ1+ϕ2)ε0\left( {{\phi _1} + {\phi _2}} \right){\varepsilon _0}(ϕ1​+ϕ2​)ε0​
View written solutionFree

Correct answer: A

  1. Use Gauss's law

    For any closed surface, Φnet=qinsideε0\Phi_{\text{net}} = \frac{q_{\text{inside}}}{\varepsilon_0}Φnet​=ε0​qinside​​ so, qinside=ε0 Φnetq_{\text{inside}} = \varepsilon_0\,\Phi_{\text{net}}qinside​=ε0​Φnet​

  2. Interpret entering and leaving flux

    • Flux leaving the closed surface is taken as positive.
    • Flux entering the closed surface is taken as negative.

    Therefore, if flux entering is ϕ1\phi_1ϕ1​ and flux leaving is ϕ2\phi_2ϕ2​, then net outward flux is Φnet=ϕ2−ϕ1\Phi_{\text{net}} = \phi_2 - \phi_1Φnet​=ϕ2​−ϕ1​

  3. Find the enclosed charge

    Using Gauss's law, qinside=ε0(ϕ2−ϕ1)q_{\text{inside}} = \varepsilon_0(\phi_2 - \phi_1)qinside​=ε0​(ϕ2​−ϕ1​)

  4. Match with the options

    This corresponds to: (ϕ2−ϕ1)ε0\boxed{(\phi_2 - \phi_1)\varepsilon_0}(ϕ2​−ϕ1​)ε0​​

    So the correct option is A.

PreviousNext

More from Electrostatics

  • A thin spherical conducting shell of radius R has a charge q. Another charge Q is placed at the center of the shell. The electrostatic potential at a point P a distance 2R​ from the center of the shell is2003 · MCQ
  • On moving a charge of 20 coulomb by 2cm,2J of work is done, then the potential differences between the points is2002 · MCQ
  • A charged particle q is placed at the centre O of cube of length L(ABCDEFGH). Another same charge q is placed at a distance L from O. Then the electric flux through ABCD is Includes diagram2002 · MCQ
  • If a charge q is placed at the center of the line joining two equal charges Q such that the system is in equilibrium then the value of q is2002 · MCQ
  • Consider two infinitely large plane parallel conducting plates as shown below. The plates are uniformly charged with a surface charge density +σ and −2σ. The force experienced by a point charge +q placed at the mid point… Includes diagram2025 · MCQ
  • A point charge +q is placed at the origin. A second point charge +9q is placed at (d,0,0) in Cartesian coordinate system. The point in between them where the electric field vanishes is:2025 · MCQ
  • A small bob of mass 100 mg and charge +10μC is connected to an insulating string of length 1 m . It is brought near to an infinitely long non-conducting sheet of charge density 'σ' as shown in figure. If string… Includes diagram2025 · MCQ
  • Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Net dipole moment of a polar linear isotropic dielectric substance is not zero even in the absence of an external…2025 · MCQ