Question 1: Reflection occurs when light bounces off a surface. The law of reflection states that the angle of incidence is equal to the angle of reflection. Explain what is meant by the 'angle of incidence' and the 'angle of reflection'.

Answer: The angle of incidence is the angle between the incoming light ray and the normal to the surface at the point of contact. The angle of reflection is the angle between the reflected light ray and the normal, which is equal to the angle of incidence.

Question 1: Describe how the law of reflection applies to a plane mirror.

Answer: In a plane mirror, the angle of incidence equals the angle of reflection for light rays reflecting off the mirror's surface, allowing the formation of a virtual image behind the mirror.

Question 2: What are the main characteristics of a reflected light ray in terms of direction and angle?

Answer: The reflected light ray leaves the surface at an angle equal to the incident angle but on the opposite side of the normal, maintaining the same angle with respect to the normal.

Question 1: A light ray strikes a mirror with an incident angle of 30 degrees. Calculate the angle of reflection and describe the path of the reflected ray.

Answer: The angle of reflection is 30 degrees. The reflected ray leaves the surface at an angle of 30 degrees on the opposite side of the normal, maintaining the same incident angle.

Question 2: If a ray of light hits a reflective surface at an incident angle of 45°, what is the angle of reflection? Express your answer in degrees.

Answer: 45 degrees

Question 1: Describe a simple experiment to demonstrate the law of reflection using a plane mirror and a torch. Include the variables involved and safety precautions.

Answer: Set up a plane mirror on a stable surface. Shine a torch beam at the mirror at a known incident angle. Use a protractor to measure the incident and reflected angles, ensuring the surface is clean and the area is free of obstructions. Variables include the incident angle, surface smoothness, and light source position. Safety precautions involve avoiding direct eye exposure to the torch beam and ensuring the setup is secure to prevent accidents.

Question 1: A boat navigates a river with a mirror-like surface. A crew member observes a reflection of the sun at an incident angle of 60°. Assuming the surface is perfectly smooth and horizontal, what is the angle of reflection? Explain the significance of this in terms of safety and navigation.

Answer: The angle of reflection is 60°. This means the reflected sunlight will also be at 60°, which could cause glare, affecting visibility and safety. Navigators must consider this reflection to avoid accidents and ensure safe passage.

Question 1: Explain how the principles of reflection are utilised in the design of periscopes used in submarines.

Answer: Periscopes use mirrors arranged at specific angles to reflect light from above the surface down to the viewer's eye, allowing observation without exposing the submarine. The law of reflection ensures the image maintains correct orientation and position.

Question 2: Discuss the importance of reflective surfaces in solar reflectors and how understanding reflection improves their efficiency.

Answer: Reflective surfaces in solar reflectors direct sunlight onto a focal point to generate heat or electricity. Understanding reflection helps in designing surfaces that maximise the concentration of sunlight, improving efficiency and energy output.