Light quiz

If the angle of incidence on a plane mirror is 35 degrees, the angle of reflection is:

Reflection from a rough surface such as cardboard is called:

The image formed by a plane mirror is:

The splitting of white light into seven colours is called:

The part of the eye that controls the size of the pupil is the:

The number of images formed by two plane mirrors kept at 90 degrees to each other is:

The point on the retina where there are no light-sensitive cells is called the:

Cone cells in the retina are sensitive to:

The Braille system was developed by:

The impression of an image persists on the retina for about:

Why is the word AMBULANCE written as a mirror image on the front of ambulances? (2 marks)

Can we see objects in a completely dark room? Give a reason. (2 marks)

Distinguish between luminous and illuminated objects, with one example of each. (2 marks)

What is lateral inversion? Give an example. (2 marks)

Why does the pupil of the eye become small in bright light? (2 marks)

How does a cinema film give the impression of continuous motion? (2 marks)

What are rods and cones? State the function of each. (2 marks)

Why do some animals, such as owls, see well at night? (2 marks)

What is the least distance of distinct vision for a normal eye? Why should we not read with a book held too close? (2 marks)

Name the parts of the eye through which light passes before reaching the retina, in order. (2 marks)

A ray of light strikes a plane mirror so that the angle between the incident ray and the reflected ray is 110 degrees. Find the angle of incidence, the angle of reflection and the angle the incident ray makes with the mirror. (3 marks)

A boy stands 3 m in front of a plane mirror fixed on a wall. He walks 1 m towards the mirror. Find (i) his new distance from the mirror (ii) the distance of his image from the mirror (iii) the change in the distance between him and his image. (3 marks)

Find the number of images formed when an object is placed between two plane mirrors inclined at (i) 120 degrees (ii) 72 degrees (iii) 30 degrees. (3 marks)

A Braille cell has 6 dot positions arranged in 3 rows of 2. Each position may be raised or flat, which gives 2^6 = 64 combinations. Excluding the pattern with no raised dot, how many dot patterns are possible? Why is the blank pattern not used as a character? (3 marks)

A film projector shows 24 still pictures per second. Find the time for which each picture is shown. Compare it with 1/16 of a second, and explain why we see smooth motion. (3 marks)

Read the passage and answer the questions. Paheli placed a plane mirror on a sheet of paper, drew a normal at a point on the mirror, and sent a thin beam of light from a torch towards that point at different angles. She measured the angles of incidence and reflection each time. (i) What relation did she find between the two angles? (ii) She bent part of the paper backwards and could no longer see the reflected ray on it. What does this show? (iii) State the two laws of reflection that she verified. (5 marks)

Read the passage and answer the questions. In a barber's shop, two large plane mirrors face each other on opposite walls. A customer sitting between them sees a long row of images of himself. (i) Why are so many images formed? (ii) Why do the images become fainter and smaller further away? (iii) What would be the number of images if the mirrors were inclined at 60 degrees to each other? (5 marks)

Read the passage and answer the questions. After a rain shower, Rahul saw a rainbow in the sky opposite the Sun. His teacher explained that tiny water droplets act like small prisms. (i) What phenomenon causes the rainbow? (ii) Name the colours of the rainbow in order. (iii) How can you produce a rainbow-like spectrum in the classroom? (5 marks)

Read the passage and answer the questions. When Meena came into a dark room from bright sunlight, she could not see anything at first, but after a few minutes she could see the objects in the room clearly. (i) What happens to the size of the pupil in bright light and in dim light? (ii) Which part of the eye controls this change? (iii) Why was she able to see after a few minutes? (5 marks)

Read the passage and answer the questions. A visually challenged student in a school reads textbooks printed in Braille and uses a white cane while walking. The school has installed ramps and textured tiles on the floors to help him move around. (i) How does the Braille system help visually challenged people to read? (ii) Name two other aids that help visually challenged people. (iii) Why should we support and include visually challenged people in all activities? (5 marks)

Draw a labelled ray diagram showing the reflection of light from a plane mirror. Describe an activity to verify the laws of reflection, and explain the difference between regular and diffused reflection with diagrams. (6 marks)

Draw a ray diagram showing how a plane mirror forms the image of a point object. List the characteristics of the image formed by a plane mirror and explain lateral inversion with an example. (6 marks)

Draw a labelled diagram of a kaleidoscope showing the arrangement of the three mirror strips and the pieces of coloured glass. Explain how it works, and how many images are formed between two mirrors at 60 degrees. (6 marks)

Draw a neat labelled diagram of the human eye. Explain the function of each part, describe the blind spot and an activity to demonstrate it, and explain persistence of vision. (6 marks)

Draw a labelled diagram showing the dispersion of white light by a prism. Explain why the colours separate, how a rainbow is formed, and describe Newton's disc activity, which shows that the seven colours together give white light. (6 marks)