A charged particle enters a uniform electric field perpendicularly. Its path is:
Answer: B
Similar to projectile motion, a charged particle in a perpendicular electric field experiences constant acceleration, resulting in a parabolic trajectory.
Q.82Easy
What is the capacitance of an isolated conducting sphere of radius R in vacuum?
Answer: A
The capacitance of an isolated conducting sphere is C = 4πε₀R = R/k, where k = 1/(4πε₀).
Q.83Easy
The energy stored in a capacitor of capacitance C charged to potential V is:
Answer: B
Energy stored in a capacitor is U = (21)CV² = (21)QV = Q²/(2C).
Q.84Easy
A conductor of arbitrary shape carries charge Q. Which is constant throughout the conductor?
Answer: B
Inside and on the surface of a conductor in electrostatic equilibrium, the potential is constant everywhere.
Q.85Easy
A parallel plate capacitor has plate area A, separation d, and dielectric constant K. Its capacitance is:
Answer: B
The capacitance of a parallel plate capacitor with dielectric is C = Kε₀A/d, where K is the dielectric constant.
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Q.86Easy
Two identical conducting spheres carry charges +Q and -Q. When brought into contact, the charge on each sphere becomes:
Answer: A
When identical conductors touch, charge redistributes equally. Total charge = Q + (-Q) = 0, so each gets 0 charge.
Q.87Easy
A Gaussian surface encloses a net charge of 5 μC. The electric flux through the surface is:
A hollow conducting sphere of radius R has total charge Q. What is the surface charge density?
Answer: B
Surface area = 4πR². Surface charge density σ = Q/(4πR²)
Q.95Easy
A parallel plate capacitor with plate area A and separation d is filled with dielectric constant κ. What is the capacitance?
Answer: B
With dielectric, C = κε₀A/d where κ is relative permittivity of dielectric
Q.96Easy
A point charge +q is placed at the origin. What is the electric potential at a distance r from the charge?
Answer: A
Electric potential due to a point charge is V = kq/r, where k is Coulomb's constant. This is a fundamental relationship in electrostatics.
Q.97Easy
An electric dipole of dipole moment p is placed in a uniform electric field E at an angle θ to the field. What is the torque acting on the dipole?
Answer: A
The torque on a dipole in a uniform field is τ = p × E = pE sin θ, which tends to align the dipole with the field.
Q.98Easy
A uniformly charged conducting sphere of radius R and total charge Q is surrounded by a concentric spherical shell. Using Gauss's law, what is the electric field at a distance r > R from the center?
Answer: A
By Gauss's law, for r > R, the electric field depends only on the enclosed charge Q and is E = kQ/r², independent of the outer shell.
Q.99Easy
The electric potential energy of a system of two point charges q₁ and q₂ separated by distance r is:
Answer: A
Potential energy of two point charges is U = kq₁q₂/r. This is positive for like charges (repulsive) and negative for unlike charges (attractive).
Q.100Easy
An electric field E = 100 V/m is applied between two parallel plates separated by distance d = 0.02 m. What is the potential difference between the plates?
Answer: A
For uniform field between parallel plates: V = Ed = 100 × 0.02 = 2 V.
