JEE Main Physics: Field due to infinitely long straight wire Practice Questions

Q1. The magnitude of the electric field due to an infinitely long straight wire is inversely proportional to:

• AThe product of charge and distance
• BThe inverse of the distance
• CThe distance
• DThe square of the distance

Q2. If the linear charge density of an infinitely long straight wire is λ, the magnitude of the electric field at a distance r from the wire is given by:

• Aλ/(2 πε₀ r)
• Bλr
• Cλ/(ε₀ r)
• Dλ/(4 πε₀ r)

Q3. The electric field intensity due to an infinitely long straight wire at a distance r from the wire is directly proportional to which quantity?

• Aπr
• B1/r²
• C1/r
• Dr

Q4. Consider the field produced by an infinite straight wire. If the distance from the wire is made three times larger, the magnitude of the electric field will be:

• AOne-third of the original value
• BNine times larger
• CNine times smaller
• DThree times smaller

Q5. The geometry of the electric field lines created by an infinite straight wire is fundamentally related to which geometric shape?

• ACircle
• BEllipse
• CHyperbola
• DParabola

Q6. If the charge per unit length (λ) of an infinite straight wire is doubled, how does the electric field strength at a fixed distance r change?

• AIt remains the same
• BIt is halved
• CIt is doubled
• DIt is quadrupled

Q7. The electric field lines produced by an infinitely long straight wire are always perpendicular to which line?

• AA line parallel to the wire
• BThe line connecting the wire to the observer
• CThe wire itself
• DA line perpendicular to the wire

Q8. The electric field lines emanating from an infinitely long straight wire are always directed:

• AAlong the line connecting the wire to the point
• BTangential to the wire
• CPerpendicular to the wire
• DParallel to the wire

Q9. The direction of the electric field at any point outside an infinitely long straight wire is:

• APerpendicular to the wire
• BIn the direction of the wire
• CTangential to the wire
• DParallel to the wire

Q10. Which of the following statements correctly describes the relationship between the electric field and the distance from an infinite wire?

• AThe field intensity is directly proportional to the distance.
• BThe field intensity is inversely proportional to the distance.
• CThe field intensity is proportional to the square of the distance.
• DThe field intensity is independent of the distance.

Q11. The electric field magnitude produced by an infinitely long straight wire depends on the distance from the wire in what manner?

• ADirectly proportional to the distance
• BInversely proportional to the square of the distance
• CInversely proportional to the distance
• DDirectly proportional to the square of the distance

Q12. An infinitely long straight wire carries a uniform linear charge density λ. If a point P is located at a distance r from the wire, which of the following statements is true regarding the electric field at P?

• AThe field is zero if P lies on the wire.
• BThe field strength is directly proportional to r.
• CThe field strength is inversely proportional to the distance r.
• DThe field magnitude depends only on the charge density λ and the permittivity ε₀ irrespective of r.

Q13. An infinitely long straight wire has a charge density λ. If the distance of a point P from the wire is halved, how does the magnitude of the electric field at P change?

• AIt becomes four times greater.
• BIt becomes one-fourth.
• CIt becomes double.
• DIt becomes half.