Q. A beam of light passes from air into a medium with a refractive index of 1.5. If the angle of incidence is 30 degrees, what is the angle of refraction? (2022)
A.
19.1 degrees
B.
20 degrees
C.
25 degrees
D.
30 degrees
Show solution
Solution
Using Snell's law, n1 * sin(i) = n2 * sin(r). Thus, sin(r) = (1 * sin(30)) / 1.5 = 0.333, giving r ≈ 19.1 degrees.
Correct Answer: A — 19.1 degrees
Learn More →
Q. A concave mirror has a focal length of 20 cm. What is the radius of curvature of the mirror? (2021)
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 →
Q. A convex lens has a focal length of 25 cm. What is the power of the lens? (2021)
A.
+2 D
B.
+4 D
C.
+6 D
D.
+8 D
Show solution
Solution
Power (P) = 1/f (in meters). Thus, P = 1/0.25 = +4 D.
Correct Answer: B — +4 D
Learn More →
Q. A lens forms a real image that is twice the size of the object. If the object distance is 10 cm, what is the image distance? (2021)
A.
10 cm
B.
15 cm
C.
20 cm
D.
25 cm
Show solution
Solution
Using the magnification formula m = -v/u, where m = 2 and u = -10 cm, we find v = -2 * (-10) = 20 cm.
Correct Answer: C — 20 cm
Learn More →
Q. A ray of light strikes a plane mirror at an angle of 30 degrees to the normal. What is the angle of reflection? (2022)
A.
30 degrees
B.
45 degrees
C.
60 degrees
D.
90 degrees
Show solution
Solution
According to the law of reflection, the angle of reflection is equal to the angle of incidence. Therefore, the angle of reflection is 30 degrees.
Correct Answer: A — 30 degrees
Learn More →
Q. An object is placed 30 cm in front of a convex lens of focal length 15 cm. What is the position of the image formed? (2020)
A.
10 cm
B.
15 cm
C.
20 cm
D.
25 cm
Show solution
Solution
Using the lens formula 1/f = 1/v - 1/u, where u = -30 cm and f = 15 cm, we find v = 10 cm.
Correct Answer: D — 25 cm
Learn More →
Q. If the wavelength of light in vacuum is 600 nm, what is its wavelength in water (n = 1.33)? (2023)
A.
450 nm
B.
600 nm
C.
750 nm
D.
800 nm
Show solution
Solution
Wavelength in medium = Wavelength in vacuum / n. Thus, λ = 600 nm / 1.33 ≈ 450 nm.
Correct Answer: A — 450 nm
Learn More →
Q. What is the critical angle for light traveling from glass (n = 1.5) to air (n = 1)? (2019)
A.
30 degrees
B.
41.8 degrees
C.
48.6 degrees
D.
60 degrees
Show solution
Solution
Using the formula sin(c) = n2/n1, we find sin(c) = 1/1.5, thus c = sin^(-1)(2/3) ≈ 41.8 degrees.
Correct Answer: B — 41.8 degrees
Learn More →
Q. What is the focal length of a diverging lens if the image distance is -15 cm and the object distance is -10 cm? (2023)
A.
-30 cm
B.
-20 cm
C.
-15 cm
D.
-10 cm
Show solution
Solution
Using the lens formula 1/f = 1/v - 1/u, we find f = -20 cm.
Correct Answer: B — -20 cm
Learn More →
Showing 1 to 9 of 9 (1 Pages)
