When light rays diverge from a point on an object and then converge to a point after passing through a lens, the image formed is described as:

• Real.
• Upright.
• Virtual.
• Enlarged.

An image that cannot be captured on a screen because light rays do not actually meet is known as:

• Real.
• Virtual.
• Magnified.
• Inverted.

The magnification of an optical system describes:

• The ratio of the image size to the object size.
• The diameter of the lens or mirror.
• The brightness of the image.
• The curvature of the lens or mirror.

When light is refracted, there is a change in its:

• Wavelength.
• Frequency.
• Both of these.
• Neither of these.

The image formed by convex lenses are:

• Always upright.
• Always real.
• Always inverted.
• Always virtual.
• None of the above.

A light ray, traveling obliquely to a concave mirror's axis, crosses the axis at the mirror's center of curvature before striking the mirror's surface. After reflection, this ray:

• Travels parallel to the mirror's axis.
• Passes through the mirror's center of curvature.
• Passes through the axis midway between the mirror's focal point and center of curvature.
• Passes through the mirror's focal point.
• Travels at right angles to the mirror's axis.

Which one of the following numbers is the correct magnification produced by a plane mirror?

• 3/2
• 1/4
• 1/2
• 1
• 2

Refraction occurs when a wavefront changes direction due to:

• A change in wave speed across a boundary.
• Entering a new medium at an angle.
• The wavefront encountering a barrier.
• The source of the wave moving.

When viewing a fish underwater from above, the fish appears closer to the surface than it actually is. This visual effect is due to:

• Diffraction.
• Dispersion.
• Reflection.
• Refraction.

The law that explains the relationship between the angle of incidence and the angle of refraction is known as:

• The Law of Reflection.
• Lenz's Law.
• Coulomb's Law.
• Snell's Law.

1. An object is placed 100 cm in front of a lens of focal length 20 cm. A second lens is placed 15 cm past the first lens. The second lens has a focal length of 40 cm. The final image:

• Is virtual and upright.
• Cannot be determined with the information given.
• Is real and upright.
• Is virtual and inverted.
• Is real and inverted.

1. If the image distance is positive, the image formed by a mirror is a(n):

• Imaginary image.
• Negative image.
• Real image.
• Positive image.
• Virtual image.

1. Single convex spherical mirrors produce images that:

• Are always larger than the actual object.
• Are always smaller than the actual object.
• Could be larger than, smaller than, or the same size as the actual object, depending on the placement of the object.
• Are always the same size as the actual object.

1. Which condition does NOT induce an emf in a loop of wire?

• Keeping the loop stationary in a uniform magnetic field without changing the field strength.
• Moving the loop into a magnetic field.
• Changing the area of the loop in a stationary magnetic field.
• Rotating the loop in a stationary magnetic field.

1. A loop of wire is placed in a steady magnetic field. If the loop is suddenly expanded, an emf is induced due to:

• The change in magnetic flux through the loop.
• The creation of a new magnetic field by the loop.
• An increase in the magnetic field strength.
• A decrease in the resistance of the loop.

1. An emf is induced in a coil due to a changing magnetic field. This induced emf is capable of:

• Increasing the coil's inductance.
• Creating a static charge on the coil.
• Driving a current through the coil.
• Permanently magnetizing the coil.

1. The electric field (E) and magnetic field (B) in an electromagnetic wave are:

• Out of phase and perpendicular to each other.
• Out of phase and parallel to each other.
• In phase and parallel to each other.
• In phase and perpendicular to each other.

1. A proton, moving east, enters a magnetic field. Because of this magnetic field, the proton curves downward. We may conclude that the magnetic field must have a component:

• Towards the west.
• Upward.
• Towards the south.
• Downward.
• Towards the north.

1. What direction does the magnetic force act on a positive charge moving in a magnetic field?

• In the direction of the magnetic field.
• In the direction of the velocity of the charge.
• Perpendicular to the direction of both the magnetic field and the velocity of the charge.
• In the opposite direction of the magnetic field.

1. The direction of the magnetic field produced by a straight current-carrying conductor can be determined by:

• Lenz's law.
• Ampre's right-hand grip rule.
• The right-hand rule.
• The left-hand rule.

1. The phenomenon by which an emf is induced by changing the magnetic flux through a loop is known as:

• Magnetic resonance.
• The Hall effect.
• Electromagnetic induction.
• The photoelectric effect.

1. A proton, moving north, enters a magnetic field of a certain strength. Because of this field, the proton curves downward. What is the direction of the magnetic field?

• Towards the north.
• Upward.
• Towards the east.
• Downward.
• Towards the west.

1. The earth's northern magnetic pole acts like:

• It has positive charge.
• It has no charge.
• It has negative charge.
• The north pole of a magnet.
• The south pole of a magnet.

1. The force experienced by a wire carrying a current I, in a magnetic field B, over a length L, is given by F = ILB when:

• L is perpendicular to B.
• L is parallel to B.
• The force does not depend on the orientation of L and B.
• The angle between L and B is 45.

1. A magnetic field exerts a force on a current-carrying wire. This force is absent when the current direction is:

• At an obtuse angle to the field lines.
• At an acute angle to the field lines.
• Perpendicular to the field lines.
• Parallel to the field lines.

1. Which force field can increase a moving electron's speed?

• Only an electric field.
• Only a magnetic field.
• Either an electric or magnetic field.
• None of these.

1. Fig. 28-4 shows three long, parallel, current-carrying wires. The current directions are indicated for currents I1 and I3. The arrow labeled F represents the magnetic force acting on current I3. The 3 currents have equal magnitudes. What is the direction of the current I2?

• Vertical upward.
• Out of the picture (in the same direction as I1 and I2).
• Vertical downward.
• Horizontal to the right.
• Into the picture (in the direction opposite to that of I1 and I3).

1. The figure below shows 2 bar magnets of the same size and the same strength. Which of the arrows labeled A to D correctly represents the direction of the magnetic field at a point located at the common origin of the arrows? (That point is at an equal distance from the two magnets.)

• The field is oriented perpendicular to the figure into the page.
• A.
• B.
• D.
• C.

1. A very long straight current-carrying wire produces a magnetic field of 20 mT at a distance d from the wire. To measure a field of 5 mT due to this wire, you would have to go to a distance from the wire of:

• 2d.
• 8d.
• 4d.
• dsquare root of (2).
• 16d.