Paper 1 Electric Fields Drills

Q1

Electric field strength at a point is defined as

A. force per unit positive test charge.
B. work done per unit charge.
C. charge per unit area.
D. potential energy per unit mass.

Q2

The electric field due to an isolated positive point charge points

A. towards the charge.
B. away from the charge.
C. clockwise around the charge.
D. only vertically downwards.

Q3

For a point charge, electric field magnitude varies with distance as

A. $1/r$.
B. $1/r^2$.
C. $r^2$.
D. constant for all $r$.

Q4

Electric potential at a point is

A. force per unit charge.
B. electric field per unit charge.
C. work done per unit positive charge in bringing it from infinity.
D. charge stored per unit p.d.

Q5

Electric potential is a

A. vector.
B. scalar.
C. unit vector.
D. dimensionless ratio.

Q6

At points on the same equipotential surface, the work done moving a charge between the points is

A. zero.
B. maximum.
C. $qE$ always.
D. equal to kinetic energy.

Q7

Electric field lines meet equipotential surfaces

A. at $45^{\circ }$.
B. parallel to them.
C. at right angles.
D. only where potential is zero.

Q8

In a uniform field between parallel plates, the field strength is approximately

A. $E=V/d$.
B. $E=Vd$.
C. $E=qV/d$.
D. $E=Fd$.

Q9

A negative charge released from rest in an electric field accelerates

A. along the electric field.
B. opposite to the electric field.
C. perpendicular to the electric field.
D. only if the field is non-uniform.

Q10

The electric potential energy change of a charge moved through p.d. $\Delta V$ is

A. $q\Delta V$.
B. $\Delta V/q$.
C. $q/\Delta V$.
D. $E/d$.

Q11

For two point charges, Coulomb force is proportional to

A. $r^2$.
B. $1/r^2$.
C. $1/r$.
D. $r$.

Q12

Electric field superposition requires adding electric fields as

A. scalars only.
B. vectors.
C. energies.
D. charges.

Q13

Electric potential from several point charges is found by adding

A. field vectors.
B. force vectors only.
C. scalar potentials algebraically.
D. only magnitudes.

Q14

A charged particle enters a uniform electric field with velocity perpendicular to the field. Its path is

A. straight with constant speed.
B. circular.
C. parabolic if field is uniform.
D. random.

Q15

The force on a charge $q$ in electric field $\vec{E}$ is

A. $\vec{F}=q\vec{E}$.
B. $\vec{F}=\vec{E}/q$.
C. $F=q/E$.
D. $F=Ed/q$.

Q16

If plate separation is halved while p.d. is unchanged, uniform field strength between plates

A. halves.
B. doubles.
C. is unchanged.
D. becomes zero.

Q17

Electric field strength has SI unit

A. $\mathrm{N}{\mathrm{C}}^{-1}$ or $\mathrm{V}{\mathrm{m}}^{-1}$.
B. $\mathrm{C}{\mathrm{N}}^{-1}$.
C. $\mathrm{J}\mathrm{C}$.
D. $\mathrm{V}\mathrm{m}$.

Q18

Near a sharp conductor tip, electric field is usually stronger because field lines are

A. more widely spaced.
B. closer together.
C. not present.
D. parallel to the conductor surface.

Q19

The potential near a positive point charge, taking zero at infinity, is

A. positive.
B. negative.
C. always zero.
D. undefined outside the charge.

Q20

A good test charge for defining field should be

A. large enough to alter the source field.
B. positive and small enough not to disturb the source field significantly.
C. negative only.
D. stationary and massive.