Light, reflection & shadows
Take your time. Show your thinking.
1. If a light ray strikes a flat mirror at an angle of incidence of 35° to the normal, what is the angle of reflection: 35° or 55°?
Light Ray (Straight Line) · Angle i = Angle r 2. What is the imaginary line drawn at 90° (perpendicular) to a mirror surface at the point where a light ray strikes called: the normal or the tangent?
Light Ray (Straight Line) · Angle i = Angle r 3. Why does a red apple appear red in white daylight: it reflects red light and absorbs other colours, or it absorbs only red light?
Light Ray (Straight Line) · Angle i = Angle r 4. Why does a straight pencil standing partly in a glass of water look bent at the water surface: refraction of light rays leaving the water, or the water bends the wood?
Light Ray (Straight Line) · Angle i = Angle r 5. In which medium does light travel fastest: in a vacuum (space) or in diamond?
Light Ray (Straight Line) · Angle i = Angle r 6. Why do people often wear light-coloured or white clothing in hot sunny weather: white surfaces reflect most sunlight and stay cooler, or white absorbs all heat?
Light Ray (Straight Line) · Angle i = Angle r 7. Why does an opaque object cast a dark shadow when placed in front of a torch: light travels in straight lines and cannot pass through the opaque object, or the object absorbs darkness?
Light Ray (Straight Line) · Angle i = Angle r 8. What optical instrument uses two mirrors angled at 45° inside a tube to let an observer see over obstacles: a periscope or a stethoscope?
Light Ray (Straight Line) · Angle i = Angle r 9. Why can sound NOT travel through the vacuum of outer space whereas light can: sound is a mechanical wave that needs vibrating particles, or space is too cold?
Light Ray (Straight Line) · Angle i = Angle r 10. At what time of day are outdoor shadows cast by the Sun shortest: around midday (noon) when the Sun is highest in the sky, or at sunrise?
Light Ray (Straight Line) · Angle i = Angle r 11. How do we see a non-luminous object such as a printed book page: light from a source reflects off the page into our eyes, or our eyes send out beams?
Light Ray (Straight Line) · Angle i = Angle r 12. What happens to the size of an object’s shadow on a wall when the object is moved closer to the small light source: the shadow gets larger, or the shadow disappears?
Light Ray (Straight Line) · Angle i = Angle r