Question

true/false - indicate whether the statement is true or false.

1. a firefly glowing in the night is an example of bioluminescence.
2. a normal is a line that is parallel to the reflected surface.
3. if the angle of reflection is 55°, then the angle of incidence will also be 55°.
4. in a convex mirror, objects appear smaller than they are in reality.
5. when an object is placed closer to a concave mirror than f, the image will always be upright and virtual.
6. the principal axis passes through the centre of curvature of the mirror.
7. refraction is a property of light in which the speed of light and its direction of travel change.
8. when a light ray travels from a medium in which its speed is slower to a medium in which its speed is faster, the refracted ray bends away from the normal.

matching - identify the term that best matches each label on the reflection diagram.

Explanation:

1. Bioluminescence is the production and emission of light by living organisms. Fireflies produce light through a chemical reaction in their bodies, which is a classic example of bioluminescence.
2. A normal in optics is a line perpendicular to the reflecting surface at the point of incidence, not parallel.
3. According to the law of reflection, the angle of reflection is equal to the angle of incidence. So if the angle of reflection is \(55^{\circ}\), the angle of incidence is also \(55^{\circ}\).
4. Convex mirrors always form virtual, upright, and diminished images. So objects appear smaller than they are in reality.
5. When an object is placed closer to a concave mirror than its focal point (\(F\)), the image formed is virtual, upright, and enlarged, not always upright (if object is beyond \(F\), image is real and inverted).
6. The principal axis of a mirror is a straight line passing through the center of curvature and the vertex (not just the center of curvature) of the mirror.
7. Refraction is the change in direction of light when it passes from one medium to another and its speed changes.
8. When light travels from a medium where its speed is slower to a medium where its speed is faster, it bends away from the normal (based on Snell's law \(n_1\sin\theta_1=n_2\sin\theta_2\), and \(v = c/n\), if \(v_2>v_1\), \(n_2 < n_1\), \(\theta_2>\theta_1\)).

Answer:

1. True
2. False
3. True
4. True
5. False
6. False
7. True
8. True