1.
Calculate the index of refraction for an object in which light travels at 1.97 x 108 m/s.
Correct Answer
E. 1.52
Explanation
The index of refraction is a measure of how much a material slows down the speed of light compared to its speed in a vacuum. In this case, the speed of light in the object is given as 1.97 x 10^8 m/s. The correct answer, 1.52, is the index of refraction that corresponds to this speed. This means that light travels approximately 1.52 times slower in this object compared to its speed in a vacuum.
2.
A light ray has an angle of incidence of 34º. The reflected ray will make what angle with the reflecting surface?
Correct Answer
C. 56º
Explanation
When a light ray reflects off a surface, the angle of incidence is equal to the angle of reflection. In this case, the angle of incidence is 34º, so the angle of reflection will also be 34º. However, since the question asks for the angle the reflected ray makes with the reflecting surface, we need to subtract the angle of reflection from 90º (since the angle of incidence and reflection form a straight line with the normal to the surface). Therefore, the angle the reflected ray makes with the reflecting surface is 90º - 34º = 56º.
3.
A YAG laser has a frequency of 2.8 x 1014 Hz. What is the wavelength of the light it produces?
Correct Answer
B. 1.1 x 10–6 m
Explanation
The wavelength of light is inversely proportional to its frequency. This means that as the frequency increases, the wavelength decreases. Since the YAG laser has a high frequency of 2.8 x 10^14 Hz, it will produce light with a short wavelength. The correct answer, 1.1 x 10^-6 m, represents a short wavelength and is therefore the most appropriate choice.
4.
A student is located 1.8 m from a plane mirror. How far is the image from the student?
Correct Answer
E. 3.6 m
Explanation
The distance between the student and the mirror is given as 1.8 m. In a plane mirror, the image formed is located at the same distance behind the mirror as the object is in front of it. Therefore, the image is also located at a distance of 1.8 m from the mirror. Since the image is formed behind the mirror, the distance from the student to the image is the sum of the distance from the student to the mirror and the distance from the mirror to the image, which is 1.8 m + 1.8 m = 3.6 m.
5.
The image in a plane mirror is
Correct Answer
D. Two of A, B, and C
Explanation
The image in a plane mirror is laterally inverted and virtual. When an object is reflected in a plane mirror, the image appears to be flipped horizontally, which is known as lateral inversion. Additionally, the image is virtual, meaning it cannot be projected onto a screen. The image is not upright, as it appears to be flipped horizontally. Therefore, the correct answer is "laterally inverted and virtual."
6.
An object is placed between F and C of a concave mirror. The image will be located:
Correct Answer
A. Beyond C
Explanation
When an object is placed between the focal point (F) and the center of curvature (C) of a concave mirror, the image formed will be located beyond the center of curvature (beyond C). This is because in this position, the rays of light from the object are reflected by the mirror and converge to form a real and inverted image beyond the center of curvature.
7.
An object is located at the focal point for a convex mirror. The image produced will be
Correct Answer
D. Upright and virtual
Explanation
When an object is located at the focal point of a convex mirror, the image produced will be upright and virtual. This is because convex mirrors always produce virtual images that are smaller than the object. The image will be upright because the light rays reflect off the mirror and diverge, creating an image that is the same orientation as the object. However, the image will be virtual because the light rays do not actually converge at a point to form a real image. Instead, they appear to diverge from a point behind the mirror, creating a virtual image that cannot be projected onto a screen.
8.
Objects placed between F and the vertex of a concave mirror will produce images that are:
Correct Answer
D. Two of A, B and C
Explanation
When an object is placed between the focal point (F) and the vertex of a concave mirror, the image formed is virtual and upright. However, the size of the image can vary. If the object is placed closer to the vertex, the image will be larger than the object. Therefore, the correct answer is "two of A, B, and C" because the images produced will be virtual and upright, but the size will depend on the specific placement of the object.
9.
Sometimes rays of light approaching curved mirrors do not all meet at the focal point. This is due to a phenomenon known as:
Correct Answer
C. SpHerical abberation
Explanation
Spherical aberration occurs when rays of light passing through a curved mirror do not all converge at a single focal point. This happens because the outer rays of the light beam focus closer to the mirror than the central rays, causing a blurred or distorted image. Refraction refers to the bending of light when it passes through different mediums, chromatic aberration is the dispersion of light into different colors, dispersion is the separation of light into its component wavelengths, and diffraction is the bending of light around obstacles or through small openings.
10.
To properly use a shaving mirror (vanity mirror) your face must be located:
Correct Answer
B. Between the focal point and the mirror
Explanation
To properly use a shaving mirror, your face must be located between the focal point and the mirror. This is because a shaving mirror is a convex mirror, which means it curves outward. In a convex mirror, the focal point is located behind the mirror. Placing your face between the focal point and the mirror allows you to see a magnified image of your face. If your face is located on the focal point or beyond the centre of curvature, the image will be distorted or appear smaller.
11.
When driving at night, headlights of cars viewed in the rearview mirror can be a distraction for the driver. This helps reduce the amount of light entering your eyes because
Correct Answer
A. Only a small percentage of light is reflected off the glass surface
Explanation
When the headlights of cars are viewed in the rearview mirror, only a small percentage of light is reflected off the glass surface. This means that most of the light is not reflected back into the driver's eyes, reducing the distraction caused by the headlights.
12.
A convex mirror of focal length 10 cm is used to create an image of a duck one-third its original height. The duck must be located:
Correct Answer
D. 20 cm from the mirror
Explanation
The image created by a convex mirror is always virtual, upright, and diminished in size. In this case, since the image is one-third the height of the original duck, it means that the image is smaller than the object. According to the mirror formula, the distance of the object (u) and the distance of the image (v) are related by the equation 1/f = 1/v - 1/u, where f is the focal length of the mirror. By substituting the given values, we can solve for u. In this case, the object distance (u) is 20 cm from the mirror, which is the correct answer.