Optics
Q. If a lens has a focal length of -20 cm, what type of lens is it?
A.
Convex lens
B.
Concave lens
C.
Biconvex lens
D.
Biconcave lens
Show solution
Solution
A negative focal length indicates that the lens is a concave lens.
Correct Answer: B — Concave lens
Learn More →
Q. If a lens has a power of -2 D, what is its focal length?
A.
-50 cm
B.
-25 cm
C.
25 cm
D.
50 cm
Show solution
Solution
Power (P) = 1/f, so f = 1/P = 1/(-2) = -0.5 m = -50 cm.
Correct Answer: B — -25 cm
Learn More →
Q. If a lens has a power of -2 D, what type of lens is it?
A.
Convex lens
B.
Concave lens
C.
Bifocal lens
D.
Plano-convex lens
Show solution
Solution
A negative power indicates a concave lens.
Correct Answer: B — Concave lens
Learn More →
Q. If a light ray enters a medium with a refractive index of 1.33 at an angle of 60°, what is the angle of refraction in the medium?
A.
30°
B.
45°
C.
60°
D.
75°
Show solution
Solution
Using Snell's law: n1 * sin(θ1) = n2 * sin(θ2), 1 * sin(60°) = 1.33 * sin(θ2) => sin(θ2) = (sin(60°)/1.33) ≈ 0.577, θ2 ≈ 35.0°.
Correct Answer: B — 45°
Learn More →
Q. If a light ray in a medium with n=1.5 strikes a boundary with n=1.0 at an angle of 70°, what will happen?
A.
Total internal reflection occurs
B.
Light refracts into the air
C.
Light is absorbed
D.
Light reflects at 70°
Show solution
Solution
Since the angle of incidence (70°) is greater than the critical angle (approximately 41.8°), total internal reflection occurs.
Correct Answer: A — Total internal reflection occurs
Learn More →
Q. If a light ray in diamond (n=2.42) strikes the diamond-air interface at an angle of 70°, will it undergo total internal reflection?
A.
Yes
B.
No
C.
Only if the angle is decreased
D.
Only if the angle is increased
Show solution
Solution
The critical angle for diamond to air is sin⁻¹(1/2.42) ≈ 24.4°. Since 70° > 24.4°, total internal reflection will occur.
Correct Answer: A — Yes
Learn More →
Q. If a light wave passes through a narrow slit and produces a diffraction pattern, what happens to the intensity of the central maximum compared to the other maxima?
A.
It is the same
B.
It is greater
C.
It is lesser
D.
It is zero
Show solution
Solution
The intensity of the central maximum is greater than that of the other maxima in a diffraction pattern.
Correct Answer: B — It is greater
Learn More →
Q. If a ray of light passes from air into a medium with a refractive index of 2, what is the angle of refraction if the angle of incidence is 30°?
A.
15°
B.
30°
C.
45°
D.
60°
Show solution
Solution
Using Snell's law: n1 * sin(θ1) = n2 * sin(θ2). 1 * sin(30°) = 2 * sin(θ2) => sin(θ2) = 0.25 => θ2 = 15°.
Correct Answer: C — 45°
Learn More →
Q. If a ray of light passes through the optical center of a lens, what happens to the ray?
A.
It bends towards the normal.
B.
It bends away from the normal.
C.
It continues in a straight line.
D.
It converges to a point.
Show solution
Solution
A ray of light passing through the optical center of a lens continues in a straight line without bending.
Correct Answer: C — It continues in a straight line.
Learn More →
Q. If light of wavelength 500 nm passes through a diffraction grating with 1000 lines/mm, what is the angle for the first-order maximum?
A.
30 degrees
B.
60 degrees
C.
45 degrees
D.
15 degrees
Show solution
Solution
Using the grating equation d sin(θ) = mλ, where d = 1/1000 mm = 1 x 10^-6 m, for m=1, we find θ ≈ 30 degrees.
Correct Answer: A — 30 degrees
Learn More →
Q. If the angle between the transmission axis of two polarizers is 90 degrees, what is the intensity of light passing through them?
A.
Maximum intensity
B.
Half of the original intensity
C.
Zero intensity
D.
Equal to the intensity of the first polarizer
Show solution
Solution
When the angle between the transmission axes of two polarizers is 90 degrees, no light passes through, resulting in zero intensity.
Correct Answer: C — Zero intensity
Learn More →
Q. If the angle between the transmission axis of two polarizers is 90 degrees, what is the transmitted intensity of light?
A.
Maximum intensity
B.
Half of the original intensity
C.
Zero intensity
D.
One-fourth of the original intensity
Show solution
Solution
When the angle between the transmission axes of two polarizers is 90 degrees, no light is transmitted, resulting in zero intensity.
Correct Answer: C — Zero intensity
Learn More →
Q. If the angle of incidence in a medium is 45° and the refractive index of the medium is 1.5, what is the angle of refraction in air?
A.
30°
B.
45°
C.
60°
D.
90°
Show solution
Solution
Using Snell's law: n1 * sin(θ1) = n2 * sin(θ2), 1.5 * sin(45°) = 1 * sin(θ2) => sin(θ2) = 1.5 * 0.7071 = 1.0607, which is not possible, hence total internal reflection occurs.
Correct Answer: C — 60°
Learn More →
Q. If the angle of incidence in a medium is 70° and the refractive index of the medium is 1.5, will total internal reflection occur?
A.
Yes
B.
No
C.
Only at certain angles
D.
Not applicable
Show solution
Solution
Since 70° > θc = sin⁻¹(1/1.5) ≈ 41.8°, total internal reflection will occur.
Correct Answer: A — Yes
Learn More →
Q. If the angle of incidence in glass (n=1.5) is 60°, will total internal reflection occur when light travels to air?
A.
Yes
B.
No
C.
Depends on the angle
D.
Not enough information
Show solution
Solution
Since the critical angle for glass to air is sin⁻¹(1.00/1.5) ≈ 41.8°, and 60° > 41.8°, total internal reflection occurs.
Correct Answer: A — Yes
Learn More →
Q. If the angle of incidence is 30° in a medium with a refractive index of 1.5, what is the angle of refraction in air?
A.
19.5°
B.
20.0°
C.
22.5°
D.
25.0°
Show solution
Solution
Using Snell's law: n1 * sin(θ1) = n2 * sin(θ2). Here, n1 = 1.5, n2 = 1.0, and θ1 = 30°. Thus, sin(θ2) = (1.5 * sin(30°))/1.0 = 0.75, leading to θ2 ≈ 48.6°.
Correct Answer: A — 19.5°
Learn More →
Q. If the angle of incidence is 70° in a medium with a refractive index of 1.5, what is the angle of refraction in air?
A.
30°
B.
20°
C.
10°
D.
Total internal reflection occurs
Show solution
Solution
Since the angle of incidence (70°) is greater than the critical angle (approximately 41.8° for glass to air), total internal reflection occurs.
Correct Answer: D — Total internal reflection occurs
Learn More →
Q. If the angle of incidence is 70° in a medium with a refractive index of 1.6, will total internal reflection occur when it hits air?
A.
Yes
B.
No
C.
Only if the angle is less than 90°
D.
Not enough information
Show solution
Solution
Critical angle θc = sin⁻¹(1/1.6) ≈ 38.7°. Since 70° > 38.7°, total internal reflection occurs.
Correct Answer: A — Yes
Learn More →
Q. If the angle of incidence is 70° in glass (n=1.5), will total internal reflection occur when light travels to air?
A.
Yes
B.
No
C.
Only if the angle of refraction is 30°
D.
Only if the angle of refraction is 45°
Show solution
Solution
The critical angle for glass to air is sin⁻¹(1/1.5) ≈ 41.8°. Since 70° > 41.8°, total internal reflection will occur.
Correct Answer: A — Yes
Learn More →
Q. If the angle of incidence is equal to the angle of refraction, what can be said about the two media?
A.
They are the same medium.
B.
They have the same refractive index.
C.
The light is traveling in a vacuum.
D.
The light is not refracted.
Show solution
Solution
When the angle of incidence equals the angle of refraction, it indicates that the light is passing from one medium to another of the same optical density, hence they are the same medium.
Correct Answer: A — They are the same medium.
Learn More →
Q. If the angle of incidence is equal to the angle of refraction, what is the medium?
A.
Vacuum
B.
Air
C.
Glass
D.
Optically denser medium
Show solution
Solution
According to Snell's law, if the angle of incidence equals the angle of refraction, the light is traveling in the same medium, which can be vacuum or air.
Correct Answer: A — Vacuum
Learn More →
Q. If the angle of incidence is equal to the critical angle, what is the angle of refraction?
A.
0°
B.
45°
C.
90°
D.
It cannot be determined.
Show solution
Solution
At the critical angle, the angle of refraction is 90°, meaning the refracted ray travels along the boundary.
Correct Answer: C — 90°
Learn More →
Q. If the angle of incidence is equal to the critical angle, what is the behavior of the light ray?
A.
It is refracted at 90°.
B.
It is totally internally reflected.
C.
It is absorbed.
D.
It is transmitted.
Show solution
Solution
When the angle of incidence equals the critical angle, the light ray is refracted along the boundary at 90°, marking the threshold for total internal reflection.
Correct Answer: A — It is refracted at 90°.
Learn More →
Q. If the critical angle for a certain material is 30°, what is the refractive index of that material?
A.
1.00
B.
1.15
C.
1.73
D.
2.00
Show solution
Solution
The refractive index n can be calculated using n = 1/sin(θc). For θc = 30°, n = 1/sin(30°) = 1/0.5 = 2.00.
Correct Answer: C — 1.73
Learn More →
Q. If the critical angle for a certain material is 45°, what is the refractive index of that material?
A.
1.41
B.
1.00
C.
1.73
D.
0.71
Show solution
Solution
Using the formula n = 1/sin(θc), where θc = 45°, we find n = 1/sin(45°) = 1/0.7071 ≈ 1.41.
Correct Answer: A — 1.41
Learn More →
Q. If the distance between the object and the image formed by a lens is 70 cm, and the object distance is 30 cm, what is the image distance?
A.
40 cm
B.
50 cm
C.
60 cm
D.
70 cm
Show solution
Solution
Image distance (v) = Object distance (u) + Distance between object and image = 30 cm + 70 cm = 40 cm.
Correct Answer: A — 40 cm
Learn More →
Q. If the distance between the slits in a double-slit experiment is increased, what happens to the interference pattern?
A.
Fringe width increases
B.
Fringe width decreases
C.
Fringe intensity increases
D.
Fringe intensity decreases
Show solution
Solution
Increasing the distance between the slits decreases the fringe width, as fringe width is inversely proportional to the slit separation.
Correct Answer: B — Fringe width decreases
Learn More →
Q. If the focal length of a concave lens is -10 cm, what is the nature of the image formed when an object is placed at 15 cm?
A.
Real and inverted
B.
Virtual and erect
C.
Real and erect
D.
Virtual and inverted
Show solution
Solution
Concave lenses always produce virtual and erect images regardless of the object distance.
Correct Answer: B — Virtual and erect
Learn More →
Q. If the focal length of a concave mirror is 10 cm, what is the radius of curvature?
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
Show solution
Solution
The radius of curvature (R) is twice the focal length (f). Therefore, R = 2f = 2 * 10 cm = 20 cm.
Correct Answer: B — 10 cm
Learn More →
Q. If the focal length of a concave mirror is 20 cm, what is the radius of curvature?
A.
10 cm
B.
20 cm
C.
30 cm
D.
40 cm
Show solution
Solution
The radius of curvature (R) is twice the focal length (f). Therefore, R = 2f = 2 * 20 cm = 40 cm.
Correct Answer: B — 20 cm
Learn More →
Showing 121 to 150 of 564 (19 Pages)