Question 1: Explain briefly what is meant by 'colour' in the context of light.

Answer: Colour in light refers to the perception of different wavelengths of visible light by the human eye, which produces the sensation of different colours.

Question 1: What is the primary source of colours in the visible spectrum?

Answer: The primary source of colours in the visible spectrum is the different wavelengths of visible light emitted or reflected by objects.

Question 2: Describe how an object appears a certain colour to our eyes.

Answer: An object appears a certain colour because it reflects that specific wavelength of light while absorbing others; the reflected light is detected by our eyes.

Question 1: Calculate the wavelength (in nanometres) of light with a frequency of 6.0 × 10^14 Hz. (Use speed of light, c = 3.0 × 10^8 m/s).

Answer: Wavelength λ = c / f = (3.0 × 10^8 m/s) / (6.0 × 10^14 Hz) = 5.0 × 10^-7 m = 500 nm

Question 2: Determine the energy (in joules) of a photon of red light with wavelength 700 nm. (Use Planck's constant, h = 6.626 × 10^-34 Js).

Answer: Energy E = h × f = h × c / λ = (6.626 × 10^-34 Js) × (3.0 × 10^8 m/s) / (700 × 10^-9 m) ≈ 2.84 × 10^-19 J

Question 1: Describe a safe method to investigate how the colour of light affects the perception of objects. Include variables to control and safety precautions.

Answer: To investigate how light colour affects object perception, set up different coloured filters (red, green, blue) over a light source illuminating objects. Control variables such as distance and intensity of light. Use safety goggles to protect eyes from intense light. Record observations of how object appearance changes with each filter, noting that the colour of the light influences the perceived colour of objects.

Question 1: A white light source is passed through a blue filter, and the transmitted light is observed to be blue. Explain why other colours are not transmitted through the filter.

Answer: Blue filters only transmit blue light because they absorb other wavelengths and allow only the wavelength corresponding to blue to pass through, which is why the transmitted light appears blue.

Question 1: Explain the difference between additive and subtractive colour mixing, providing examples of each.

Answer: Additive colour mixing occurs when different colours of light are combined, resulting in a mixture that can produce white light (e.g., red, green, and blue light combined). Subtractive colour mixing involves mixing pigments or dyes, where each absorbs certain wavelengths and reflects others; combining cyan, magenta, and yellow pigments can produce various colours, but typically results in black when mixed fully.

Question 1: Identify one industry or technology that relies heavily on the principles of colour and light, and explain its importance.

Answer: Display technology, such as LED screens and televisions, relies on understanding how different colours of light are produced and combined to create vivid images, making knowledge of colour essential for colour accuracy and quality.