Light, mirrors and lensesIB MYP Physics: Mind map

Exam questions on Light, mirrors and lenses

1. A group of students build a pinhole camera from a cardboard tube. One end is closed with foil that has a tiny hole in the middle, and the other end is covered with tracing paper that acts as a screen. They point the hole at a lit candle in a dark room and see an image of the flame on the screen.
   The students move the camera closer to the candle. State what happens to the size of the image and explain why.2 marks
2. Amira is short-sighted. Light from distant objects is focused in front of her retina, so distant objects look blurred, and she wears glasses to correct this. Her brother Idris is long-sighted, and he uses a magnifying glass to read the small print on medicine packets.
   State the type of lens in Idris's magnifying glass and describe the image he sees.2 marks
3. A student investigates how the shape of a converging lens affects its focal length. She holds each lens so that light from a distant window passes through it, then moves a white card behind the lens until a sharp image of the window forms. She measures the distance from the lens to the card. Lens P is thin and only slightly curved, lens Q is thicker, and lens R is the thickest and most strongly curved. Her results are 30 cm for P, 15 cm for Q and 6 cm for R.
   Identify the independent variable, the dependent variable and one control variable in this investigation.3 marks