Physics Gr 11 Practice Sheet 2024-2025 PDF

2024-2025 TERM 1 Final (Physics) Gr 11 Practice sheet (Illumination, The wave nature of light, Physics of music,Wave behavior ) 1. The bending of light as it passes the edges of a barrier is calle...

2024-2025 TERM 1 Final (Physics) Gr 11 Practice sheet (Illumination, The wave nature of light, Physics of music,Wave behavior ) 1. The bending of light as it passes the edges of a barrier is called diffraction. 2. Huygen’s wavelets combine to form a straight wavefront, except at the edges of the wave. The wavelets spread out in a circular manner when a barrier creates an edge. 3. When a narrow beam of sunlight or white light passes through a glass prism, it splits into different colors. 4. As white light crosses the boundary from air into glass and back into air, its wave nature causes each different color of light to be bent, or refracted, at a different angle. 5. This unequal bending of the different colors causes the white light to be spread into a spectrum. 6. Light has wave properties, and each color of light is associated with a wavelength. 7. Light falls within the range of wavelengths from about 400 nm to 700 nm. A. Vision: - Providing high-quality education and an environment that builds educational and life skills, enhancing religious values and noble principles to serve the community. B. Mission: - To become one of the best educational institutions locally and internationally based on the best educational standards and a well-planned system that aligns with global needs. 8. White light can be formed by adding red, green, and blue light in equal amounts. For this reason, red, green, and blue are each called a primary color, this is called the additive color process. 9. The primary colors can be mixed in pairs to form three additional colors. 10.The colors yellow, cyan, and magenta are each called a secondary color, because each is a combination of two primary colors. 11.Complementary colors are two colors of light that can be combined to make white light. 12.The color of an object depends on the wavelengths present in the light that illuminates the object, and on which wavelengths the object absorbs and which it reflects. The existence of dyes in a material or pigments on its surface give the object color. 13.A pigment that absorbs only one primary color and reflects two from white light is called a primary pigment. 14.A pigment that absorbs two primary colors and reflects one color is called a secondary pigment. 15.Polarization is the production of light with a specific pattern of oscillation. When the electric field of a light wave oscillates in random directions, the light is nonpolarized. 16.Sound is produced by a vibrating object. The vibrations of the object create particle motions that cause pressure oscillations in the air. 17.How human voice produced: The human voice is produced by vibrations of the vocal cords, which are two membranes located in the throat. Air from the lungs rushing through the throat starts the vocal cords vibrating. 18.The length of the air column determines the frequencies of the vibrating air that will be set into resonance. 19.A resonating tube with one end closed to air is called a closed-pipe resonator. 20.An open-pipe resonator is a resonating tube with both ends open that also will resonate with a sound source. 21.Open-pipe resonators include flutes and saxophones. The sound wave does not reflect off a closed end, but rather off an open end. 22.The pressure of the reflected wave is inverted in an open pipe and not inverted in a closed pipe 23. 24.precision: a characteristic of a measured value describing the degree of exactness of a measurement 25.In the ray model of light, light is represented as a ray that travels in a straight path, the direction of which can be changed only by placing an obstruction in the path. 26.In this module, we assume for the purpose of simplification that all light sources are point sources 27.Rays of light come from sources of light. Objects such as the Sun that emit their own light are luminous sources. 28.Objects you see due to light reflecting from them, such as the Moon, are illuminated sources. 29. 30.A medium, such as brick, that does not transmit light but that reflects and absorbs light is opaque. 31.Mediums that transmit most light, such as air and glass, are transparent. 32.A medium that transmits and reflects light but that does not permit objects to be seen clearly through it, such as frosted glass, is translucent. 33.Transparent or translucent media not only transmit light, but also reflect a fraction of the light. 34.With the ray model of light, a source that is brighter produces more light rays than a less bright source. 35.The rate at which light energy is emitted from a luminous source is called the luminous flux (P). 36.The unit of luminous flux is the lumen (lm). 37.The luminous flux falling on a given surface area at any instant is called illuminance (E). 38.It is measured in lux (lx), which is equivalent to lumens per square meter (lm/m2). 39.As the light rays spread out in straight lines in all directions from a point source, the number of light rays that illuminate a unit of area decreases as the square of the distance from the point source. 40.Some luminous sources are specified in candelas (cd). A candela is not a measure of luminous flux but of luminous intensity 41.The wave that strikes the boundary is called the incident wave. 42.If some of the energy of the incident wave is reflected backward, the returning wave is called the reflected wave. 43.The principle of superposition states that the displacement of a medium caused by two or more waves is the algebraic sum of the displacement caused by the individual waves.  44.The result of the superposition of two or more waves is called interference. 45.A standing wave is a wave that appears to be standing still, produced by the interference of two waves moving in opposite directions. 46.The law of reflection states that the angle of incidence is equal to the angle of reflection. 47. 48.Because the waves in the shallow water are generated by the waves in the deep water, their frequency is not changed. 49.Based on the equation λ = v/f, the decrease in the speed of the waves means that the wavelength is shorter in the shallower water.