Q 1 :    

An electric field is given by (6i^+5j^+3k^)N/C. The electric flux through a surface area 30i^  m2  lying in YZ-plane (in SI unit) is              [2024]

  • 180

     

  • 90

     

  • 150

     

  • 60

     

(A)       E=(6i^+5j^+3k^)N/C

             A=30i^ m2

            Electric flux, ϕ=E·A

            ϕ=(6i^+5j^+3k^)·(30i^)=180Nm2C

 



Q 2 :    

Three infinitely long charged thin sheets are placed as shown in figure. The magnitude of electric field at the point P is xσε0. The value of x is _____ (all quantities are measured in Sl units).              [2024]



(2)       E=E1+E2+E3

            =σ2ε0(-i^)+-2σ2ε0(i^)+-σ2ε0(i^)

             =-4σ2ε0i^=2σε0(-i^)

 



Q 3 :    

A charge q is placed at the center of one of the surfaces of a cube. The flux linked with the cube is          [2024]

  • q2ε0    

     

  • q4ε0

     

  • q8ε0    

     

  • zero

     

(1)

ϕtotal=qenε0

Let us enclose the charge with an identical cube as shown,

Total flux, 2ϕ=qε0ϕ=q2ε0



Q 4 :    

Five charges +q, +5q, −2q, +3q and −4q are situated as shown in the figure. The electric flux due to this configuration through the surface S is        [2024]

  • 5qε0 

     

  • 4qε0

     

  • 3qε0

     

  • qε0

     

(2)

As per Gauss' theorem,

ϕ=qinε0=q+(-2q)+5qε0=4qε0



Q 5 :    

Two charges of 5Q and −2Q are situated at the points (3a,0) and (−5a,0) respectively. The electric flux through a sphere of radius 4a having center at origin is      [2024]

  • 2Qε0

     

  • 5Qε0

     

  • 7Qε0

     

  • 3Qε0

     

(2)

If we draw the sphere, the charge -2Q will be outside of sphere and 5Q charge is inside the spherical region

The flux through sphere 5Qε0



Q 6 :    

C1 and C2 are two hollow concentric cubes enclosing charges 2Q and 3Q respectively as shown in the figure. The ratio of electric flux passing through C1 and C2 is    [2024]

  • 2 : 5

     

  • 5 : 2

     

  • 2 : 3

     

  • 3 : 2

     

(1)

Flux through C1ϕ1=qinε0=2Qε0

Flux through C2ϕ2=qinε0=2Q+3Qε0=5Qε0

C1C2=ϕ1ϕ2=2Q/ε05Q/ε0=25



Q 7 :    

An infinite plane sheet of charge having uniform surface charge density +σs C/m2 is placed on the x-y plane. Another infinitely long line charge having uniform linear charge density +λeC/m is placed at z=4 m plane and parallel to the y-axis. If the magnitude values σs=2λethen at point (0,0,2), the ratio of magnitudes of electric field values due to sheet charge to that of line charge is πn:1. The value of n is ______ .       [2024]



(16)

Esheet=σs2ε0k^=λeε0k^

Ewire=2kλer(-k^)=2kλe2(-k^)=kλ(-k^)

|Esheet||Ewire|=λeε0×1kλe=1ε0k=1ε0×14πε0=4π

4π=πnn=16



Q 8 :    

An electric field, E=2i^+6j^+8k^6 passes through the surface of 4m2 area having unit vector n^=(2i^+j^+k^6). The electric flux for that surface is ____ Vm.   [2024]



(12)

ϕ=E·A=(2i^+6j^+8k^6)·4(2i^+j^+k^6)

ϕ=46×(4+6+8)=12 Vm



Q 9 :    

An electric field E=(2xi^)NC-1 exists in space. A cube of side 2 m is placed in the space as per figure given below. The electric flux through the cube is _____ Nm2/C.  [2024]



(16)

Given E=(2xi^) N/C

ϕ=E·A

ϕin=-4×4=-16 Nm2/C

ϕout=8×4=32 Nm2/C

ϕnet=ϕin+ϕout=-16+32=16 Nm2/C