Light

1. What type of lens is used in a magnifying glass?

• A) Concave lens
• B) Convex lens
• C) Plano-concave lens
• D) Cylindrical lens

2. Why does a fish in transparent water appear to be at a shallower position than it actually is?

• A) Because the water reflects the light, creating a mirror image.
• B) Because the light rays from the fish are absorbed by the water.
• C) Because of the total internal reflection of light at the water's surface.
• D) Because light from the fish refracts and bends away from the normal as it passes from water to air, creating a virtual image.

3. What is the phenomenon called when a ray of light bends as it crosses from one transparent medium to another?

• A) Reflection
• B) Refraction
• C) Total internal reflection
• D) Dispersion

4. According to the text, how does a pencil partially immersed in water appear?

• A) Longer and thinner
• B) Perfectly straight
• C) Shorter, thicker and broken
• D) Invisible under the water

5. Which part of the human eye is described as a light-sensitive, rose-colored translucent membrane?

• A) Cornea
• B) Pupil
• C) Sclera
• D) Retina

6. What is a primary use of optical fibres in the medical field?

• A) To perform laser eye surgery
• B) To measure blood pressure
• C) To examine internal parts of the human body like the stomach
• D) To create lenses for spectacles

7. What are the two necessary conditions for total internal reflection to occur?

• A) Light travels from rarer to denser medium, and the angle of incidence is less than the critical angle.
• B) Light travels from denser to rarer medium, and the angle of incidence is greater than the critical angle.
• C) Light travels from denser to rarer medium, and the angle of incidence is equal to the critical angle.
• D) Light travels from rarer to denser medium, and the angle of incidence is greater than the critical angle.