Chapter 2: Ray Optics and Optical Instruments — Online MCQ Test
PHYSICS · CLASS 12 INTERMEDIATE 2 YEAR · Telangana State Board
Practice Chapter 2: Ray Optics and Optical Instruments with a free chapter-wise online MCQ test.
This chapter covers: This chapter details reflection total internal reflection refraction at spherical surfaces lens formulas magnification prism dispersion and optical instruments including microscope....
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Chapter 2: Ray Optics and Optical Instruments — Important Questions & Answers
What is the principal focus of a convex lens?
- A. The point where parallel rays converge after refraction
- B. The center of the lens through which light passes undeviated
- C. The point where all rays from the focus become parallel
- D. The point where reflected rays appear to diverge
Answer: A. The point where parallel rays converge after refraction
A convex lens converges parallel rays to a point called the principal focus. This is a basic defining property of a converging lens.
A convex lens converges parallel rays to a point called the principal focus. This is a basic defining property of a converging lens.
Which of the following is the SI unit of the power of a lens?
- A. dioptre
- B. metre
- C. joule
- D. newton
Answer: A. dioptre
The power of a lens is measured in dioptres (D), where 1 D = 1 m^-1. It indicates the converging or diverging ability of the lens.
The power of a lens is measured in dioptres (D), where 1 D = 1 m^-1. It indicates the converging or diverging ability of the lens.
A ray of light passes from glass to air. Which of the following is true when the angle of incidence is greater than the critical angle?
- A. The ray bends away from the normal and emerges
- B. The ray bends towards the normal and emerges
- C. The ray is totally internally reflected
- D. The ray is absorbed completely
Answer: C. The ray is totally internally reflected
When light travels from a denser to a rarer medium and the incidence angle exceeds the critical angle, total internal reflection takes place. No refraction occurs into the rarer medium.
When light travels from a denser to a rarer medium and the incidence angle exceeds the critical angle, total internal reflection takes place. No refraction occurs into the rarer medium.
Which of the following statements about a concave mirror is NOT correct?
- A. It can form a real image
- B. It can form a virtual image
- C. It always forms an erect image
- D. It can magnify the image
Answer: C. It always forms an erect image
A concave mirror can form both real and virtual images depending on object position, and the image may be erect or inverted. Therefore, it does not always form an erect image.
A concave mirror can form both real and virtual images depending on object position, and the image may be erect or inverted. Therefore, it does not always form an erect image.
A prism of angle A produces minimum deviation δm for a ray. Which relation is correct for refractive index n of the prism material?
- A. n = sin((A + δm)/2) / sin(A/2)
- B. n = sin(A/2) / sin((A + δm)/2)
- C. n = (A + δm)/A
- D. n = sin δm / sin A
Answer: A. n = sin((A + δm)/2) / sin(A/2)
At minimum deviation, the prism is in the symmetric position and the standard relation is n = sin((A + δm)/2) / sin(A/2). This formula is frequently used in prism problems.
At minimum deviation, the prism is in the symmetric position and the standard relation is n = sin((A + δm)/2) / sin(A/2). This formula is frequently used in prism problems.