1. The phenomenon of light bending as it passes from one medium to another is known as:
Answer:
Explanation:
Refraction occurs when light changes its speed and direction as it moves from one medium to another.
2. The angle of incidence for which the angle of refraction becomes 90° is called:
Answer:
Explanation:
Beyond the critical angle, total internal reflection occurs.
3. Which of the following lenses can produce both real and virtual images?
Answer:
Explanation:
A convex lens can produce both real and virtual images based on the position of the object.
4. The splitting of white light into its constituent colors is termed as:
Answer:
Explanation:
Dispersion occurs due to the different wavelengths of light refracting by different amounts.
5. Which instrument uses the principle of total internal reflection?
Answer:
Explanation:
Optical fibers transmit light signals based on the principle of total internal reflection.
6. The image formed by a plane mirror is:
Answer:
Explanation:
A plane mirror always forms a virtual, erect, and same-sized image as the object.
7. The focal length of a convex lens is:
Answer:
Explanation:
For a convex lens, the focal length is taken as positive as per the lens formula convention.
8. If the magnification produced by a lens is negative, it means:
Answer:
Explanation:
A negative magnification indicates a real and inverted image.
9. Which of the following optical instruments uses a combination of lenses?
Answer:
Explanation:
A compound microscope uses a combination of two convex lenses.
10. The mirror used by dentists to see the enlarged image of teeth is:
Answer:
Explanation:
Concave mirrors can produce magnified images when the object is close.
11. Which of the following phenomena is responsible for the blue color of the sky?
Answer:
Explanation:
Shorter wavelengths like blue scatter more than longer wavelengths, giving the sky its blue color.
12. A lens which is thicker at the center than at the edges is:
Answer:
Explanation:
A convex lens bulges outwards and is thicker in the middle than at the edges.
13. When parallel rays of light hit a concave mirror, they:
Answer:
Explanation:
A concave mirror converges parallel rays of light at its focus.
14. The image formed by a convex lens is real, inverted, and magnified when the object is:
Answer:
Explanation:
For objects placed between F (focus) and 2F (twice the focal length), the convex lens forms a real, inverted, and magnified image.
15. The distance between the optical center of a lens and its focus is called:
Answer:
Explanation:
The focal length is the distance from the optical center to the focus of the lens.
16. In a ray diagram, the line passing through the center of curvature and the pole of a mirror is termed:
Answer:
Explanation:
The principal axis is a straight line passing through the center of curvature and the pole of the mirror.
17. A rainbow is formed due to:
Answer:
Explanation:
A rainbow is formed due to the dispersion of sunlight and its internal reflection inside water droplets.
18. If the refractive index of diamond is 2.42, it implies:
Answer:
Explanation:
Refractive index indicates how much light slows down when entering a medium.
19. The phenomenon in which light bends around obstacles in its path is called:
Answer:
Explanation:
Diffraction refers to the bending of light waves around obstacles or the spreading of light waves as they pass through a narrow opening.
20. In a convex mirror, the image formed is always:
Answer:
Explanation:
A convex mirror forms a virtual, erect, and usually diminished image.