Home
Class 12
PHYSICS
An electric dipole has a fixed dipole mo...

An electric dipole has a fixed dipole moment `vecp`, which makes angle `theta` with respect to x-aixs. When subjected to an electric field `vec(E)_(1)=Ehati`, it experiences a torque `vec(T)_(1)=tauhatk`. When subjected to another electric field `vec(E)_(2)=sqrt3Ehatj` it experiences a torque `vec(T)_(2)=-vec(T)_(1)`. The angle `theta` is

A

`30^(@)`

B

`45^(@)`

C

`60^(@)`

D

`90^(@)`

Text Solution

Verified by Experts

The correct Answer is:
C
Since the dipole makes and anglt `theta` with the x-axis,
`:.vec(P)=pcosthetahati+p""sinthetahatj`

`:.vec(T)_(1)=vec(p)xxvec(E)_(1)=(pcosthetahati+p""sinthetahatj)xx(Ehatj)`
or, `tauhatk=-pEsinthetahatk" ".......(1)`
and `vec(T)_(2)=vecpxxvec(E)_(2)`
or, `-vec(T)_(1)=(pcosthetahati+p""sinthetahatj)xxsqrt3E_(1)hatj`
or, `-tau hat k=(pcosthetahati+p""sinthetahatj)xxsqrt3Ehatj" "[:'E_(1)=E]`
`=sqrt3pEcosthetahatk`
or, `tauhatk=-sqrt3pEcosthetahatk" ".......(2)`
Comparing (1) and (2),
`pEsintheta=sqrt3pEcostheta`
or, `theta=60^(@)`
Promotional Banner

Topper's Solved these Questions

  • ELECTRIC FIELD

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE ( AIPMT)|1 Videos

  • ELECTRIC FIELD

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE ( NEET )|4 Videos

  • ELECTRIC FIELD

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE (WBJEE)|13 Videos

  • ELECTRIC ENERGY AND POWER

    CHHAYA PUBLICATION|Exercise CBSE SCANNER|7 Videos

  • ELECTRIC POTENTIAL

    CHHAYA PUBLICATION|Exercise CBSE Scanner|13 Videos

Similar Questions

Explore conceptually related problems

Obtain the expression for the torque vec(tau) experienced by an electric dipole of dipole moment vec(p) in a uniform electric field, vec(E) .

An electric dipole placed at an angle of 30^(@) with a uniform electric field of intensity 10^(4)N.C^(-1) experiences a torque of 9xx10^(-26)N.m . What is the moment of the electric dipole?

Derive the expression for the potential energy of an electric dipole of dipole moment vec(p) placed in a uniform electric field vec(E ) .

An electric dipole is placed at an angle of 30^@ with an electric field intensity 2xx10^5N//C . It experiences a torque equal to 4 Nm. The charge on the dipole, if the dipole length is 2 cm, is

An electric field is expressed as vec(E ) = hat(i)x + hat(k)z . What is the potential difference (in volt) between A(0,0,0) and B(2,2,0)?

Determine how much work is to be done to move a 10 C positive charge 1 m along the y-axis in a uniform electric field vec(E ) - 5(hat(i) + hat(j)) V cdot m^(-1) .

A plane electromagnetic wave is moving along X-direction in free space. At a certain location in a moment the electric field vector vec E = E_0 sin (wt - kx) hatj , where E_0 = 3 V/m. Write down the expression for the magnetic field vector vec B in that location.

The dipole moment of an electric dipole is given by vecp=10^(-7)(5hati+hatj-2hatk)cm . The dipole is kept in an electric field of intensity, vecE=10^(7)(hati+hatj+hatk)V.m^(-1) . Obtain the magnitude of torque acting on the dipole.

The charge of an electric dipole is 10muC and length 20 mm. It is placed along an electric field of intensity 10^(3)N.C^(-1) . What is the net force acting on the dipole ? If the dipole is placed at an angle of 60^(@) with the electric field, what amount of torque will act on it?

An electric field is expressed as vec E = ( 5 hati + 3 hatj + 2 hatk ) unit. Find out the electric flux across an area of 200 unit on the yz - plane in the field.