Dive into the world of optics and test your understanding of light, reflection, and refraction with these multiple-choice questions. Each question is accompanied by the correct answer and a concise explanation.
1. What is the angle of reflection when a light ray strikes a mirror perpendicularly?
Answer:
Explanation:
The angle of incidence is 0° when a light ray strikes perpendicularly. According to the law of reflection, the angle of incidence is equal to the angle of reflection. Therefore, the angle of reflection is also 0°.
2. Which of the following mediums has the highest speed of light?
Answer:
Explanation:
The speed of light is highest in air compared to other given mediums. The denser the medium, the slower light travels through it.
3. When light travels from air into water, it bends towards:
Answer:
Explanation:
When light travels from a rarer medium (air) to a denser medium (water), it slows down and bends towards the normal.
4. What is the refractive index of a medium if the speed of light in it is equal to the speed of light in a vacuum?
Answer:
Explanation:
The refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. If they are equal, the ratio is 1.
5. A lens that converges a parallel beam of light is called:
Answer:
Explanation:
A convex lens is thicker in the middle than at the edges, making it converge a parallel beam of light.
6. In a concave mirror, if an object is placed between the focal point and the mirror, the image formed is:
Answer:
Explanation:
For a concave mirror, when an object is placed between the focal point and the mirror, the image formed is virtual, erect, and magnified.
7. The focal length of a plane mirror is:
Answer:
Explanation:
A plane mirror has parallel rays, so its focal point is considered to be at infinity, making its focal length also infinite.
8. The lateral inversion in a plane mirror means:
Answer:
Explanation:
In a plane mirror, left appears as right and vice versa. This is termed lateral inversion.
9. Critical angle is the angle of incidence for which the angle of refraction is:
Answer:
Explanation:
The critical angle is defined as the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90°.
10. Total internal reflection can occur when light travels from:
Answer:
Explanation:
Total internal reflection occurs when light travels from a denser medium to a rarer medium, and the angle of incidence is greater than the critical angle.
11. Which color of light has the highest refractive index in a prism?
Answer:
Explanation:
Different colors of light have different speeds in a prism. Blue light bends the most and hence has the highest refractive index.
12. A ray of light incident on a mirror makes an angle of 30° with the mirror. The angle of reflection is:
Answer:
Explanation:
According to the law of reflection, the angle of incidence is equal to the angle of reflection.
13. Convex mirrors are preferred for rear-view mirrors in vehicles because they:
Answer:
Explanation:
Convex mirrors provide a wider field of view as they give a diminished and erect image.
14. The phenomenon due to which the bottom of a swimming pool appears raised is called:
Answer:
Explanation:
The bending of light as it moves from water to air makes the bottom of the pool appear nearer or raised.
15. Which of the following is not a property of the image formed by a plane mirror?
Answer:
Explanation:
The image formed by a plane mirror is always of the same size as the object and is neither magnified nor diminished.