Question 1

Which of the following statements about electric charge is correct?

Accepted Answer

None of the statements are true.

Question 2

A single charge $$q = +1\ \mu\mathrm{C} is $$located at the origin and surrounded by four different objects: A and B are point charges 50 cm away, C is a spherical metal shell (radius 15 cm, center 50 cm on the y-axis), and D is a solid metal sphere (radius 15 cm, center 50 cm on the z-axis). If charge $$q is $$allowed to move freely, in which direction would it start moving?

Accepted Answer

It doesn’t move.

Question 3

An electron is initially moving to the right with speed $$v$$ when it enters a uniform electric field directed upwards. Which trajectory will the electron follow?

Accepted Answer

C (curves downward)

Question 4

Refer to the electric field diagram with charges P and Q. Consider the statements: (i) The charge on P is smaller than the charge on Q. (ii) The electrostatic force on P is smaller than the force on Q. Which is correct?

Accepted Answer

Only (i) is true.

Question 5

When an electron enters an electric field and follows a curved trajectory, which statement best describes its electric potential energy as it moves?

Accepted Answer

It is moving from low potential to high potential and gaining electric potential energy.

Question 6

A battery charges a parallel-plate capacitor fully and is then removed. The plates are slowly pulled apart. Which of the following will happen?

Accepted Answer

(i) and (iii)

Question 7

Which statement is NOT true for a perfect conductor placed in a steady external electric field?

Accepted Answer

The surface of the conductor is electrically neutral.

Question 8

Two parallel-plate capacitors store the same charge $$Q. $$The plates are separated by the same distance and have identical areas. Capacitor 2 is filled with a dielectric ($$\kappa \u003e 1). $$Which is true?

Accepted Answer

Only (ii): The potential energy stored in Capacitor 1 is larger than that in Capacitor 2.

Question 9

A parallel-plate capacitor with plate spacing $$d = 1\ \mathrm{mm} is $$charged to $$500\ \mathrm{V}. A $$proton is fired through a hole in the negative plate with speed $$4.0 	imes 10^5$\ \mathrm{m/s}. $$Which of the following statements about the solution steps is NOT true?

Accepted Answer

The final answer in (3) suggests that the proton will stop before it strikes the positive plate.

Question 10

The condition for dark fringes in single-slit interference is $$W \sin 	heta = m \lambda$$, $$m = \pm 1, \pm 2, \pm 3, .... $$Which change increases the separation between bright fringes in the diffraction pattern?

Accepted Answer

(i) Increase the wavelength of the light used.

Question 11

For a successful Young’s double-slit experiment, the light source must be both monochromatic and coherent.

Accepted Answer

True

Question 12

Electrically neutral objects cannot exert an electrical force on each other, but they can exert a gravitational force on each other.

Accepted Answer

True

Question 13

As a proton moves in a direction perpendicular to electric field lines, what happens to its electric potential and electric potential energy?

Accepted Answer

Both remain constant.

Question 14

A hydrogen nucleus ($$+e) is to $$the left of a carbon nucleus ($$+6e). $$The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is greater than the force exerted on the carbon nucleus.

Accepted Answer

False

Question 15

If the electric potential at a point in space is zero, then the electric field at that point must be zero.

Accepted Answer

False

Question 16

A parallel-plate capacitor is charged and then disconnected from the battery. If the plate separation is doubled, what happens to the energy stored in the capacitor?

Accepted Answer

It doubles.

Question 17

A dielectric material is inserted between the plates of a charged capacitor (battery disconnected). What happens to the electric field between the plates?

Accepted Answer

It decreases.

Question 18

Which of the following best describes why the electric field inside a conductor is zero in electrostatic equilibrium?

Accepted Answer

Free electrons move to cancel any internal field.

Question 19

A student claims that increasing the slit width in a single-slit diffraction experiment will increase the separation between bright fringes. Is this correct?

Accepted Answer

No, increasing slit width decreases fringe separation.

Question 20

A proton is released from rest in a uniform electric field. Which of the following equations correctly describes the work done by the field as the proton moves a distance $$d$$?

Accepted Answer

$$W = qEd$$

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