NEET2026PhysicsChapterActual
An electric dipole consisting of two opposite charges of magnitude 4 C separated by a distance of 5 cm is placed in a uniform electric field. If the maximum torque experienced by the dipole is 0.2 N m , which of the following correctly gives the magnitude of the electric field ( E ) and the torque ( ) when the dipole is oriented at 30^ to the field?
Options
- AE = 10^6 N C ⁻¹ and = 0.1 3 N m
- BE = 2 10^6 N C ⁻¹ and = 0.1 N m
- CE = 10^6 N C ⁻¹ and = 0.1 N m
- DE = 2 10^6 N C ⁻¹ and = 0.1 3 N m
Correct answer
C. E = 10^6 N C ⁻¹ and = 0.1 N m
Step-by-step solution
The dipole moment is given by p = qd . Substituting the given values: p = (4 10⁻⁶ C ) (5 10⁻² m ) = 2 10⁻⁷ C m The maximum torque experienced by the dipole is _ max = pE . 0.2 = (2 10⁻⁷) E E = 0.2 2 10⁻⁷ = 10^6 N C ⁻¹ The torque at an angle = 30^ is given by = pE . = _ max 30^ = 0.2 1 2 = 0.1 N m Answer: E = 10^6 N C ⁻¹ and = 0.1 N m