Light: Shadows and Reflections — Quiz

Q1. A plane mirror placed in sunlight throws a bright spot on a wall. The mirror is

• A. a luminous object because it lights the wall.
• B. a translucent object because light passes through it.
• C. a transparent object because it is shiny.
• D. a non-luminous object because it only reflects the Sun's light.

Q2. In Activity 11.1, Ravi moves the middle matchbox slightly to one side. The bright spot on the screen now

• A. disappears, showing that light travels in a straight line.
• B. becomes brighter and larger.
• C. splits into two spots of equal brightness.
• D. stays unchanged because torchlight bends.

Q3. Priya holds a piece of clear window glass and a piece of cardboard in front of a torch. She finds that

• A. both block light fully.
• B. the glass lets light pass almost completely while the cardboard blocks it.
• C. both let light pass partially.
• D. the cardboard lets more light through than the glass.

Q4. In Activity 11.4, the colour of an opaque object is changed. The colour of its shadow on the screen

• A. becomes the same as the new colour.
• B. becomes the complementary colour.
• C. does not change.
• D. becomes brighter than before.

Q5. A torch, an opaque ball and a screen are arranged in a line. If the torch is moved closer to the ball, keeping the screen fixed, the shadow on the screen will become

• A. smaller.
• B. of the same size.
• C. fainter and disappear.
• D. larger.

Q6. Asha measures her shadow at 9 AM, 12 noon and 4 PM on a sunny day. Her shadow will be the shortest at

• A. 9 AM.
• B. 12 noon.
• C. 4 PM.
• D. the three times are equal.

Q7. Reshma tilts a polished steel plate in sunlight and a bright spot appears on a wall not directly in the Sun. The best explanation is that the steel plate

• A. emits its own light.
• B. is transparent to sunlight.
• C. reflects sunlight and changes its direction.
• D. absorbs sunlight and re-emits it.

Q8. Activity 11.7 asks students to place a screen behind a plane mirror to catch the image of a pen. What will the student observe?

• A. A clear inverted image on the screen.
• B. A clear erect image on the screen.
• C. No image is obtained on the screen.
• D. Two images, one inverted and one erect.

Q9. Standing in front of a plane mirror, Patrick raises his left arm. In the mirror image, the arm that appears raised is the

• A. right arm.
• B. left arm.
• C. both arms.
• D. neither arm — the image appears inverted upside down.

Q10. In the sliding pinhole camera (Activity 11.10), the screen on the smaller box is made of tracing paper because

• A. tracing paper is transparent and lets the full image through.
• B. tracing paper is opaque and blocks light.
• C. tracing paper is luminous and glows.
• D. tracing paper is translucent — light reaches it but it diffuses enough to show the image.

Q11. Periscopes are commonly used in

• A. submarines and tanks to look outside.
• B. ordinary household lamps.
• C. calculator displays.
• D. X-ray machines in hospitals.

Q12. Ravi makes a kaleidoscope using three rectangular plane mirrors joined in a triangle. The many beautiful patterns he sees are due to

• A. absorption of light by glass.
• B. multiple reflections of light in the three mirrors.
• C. the colour of the cardboard tube.
• D. refraction in the tracing paper.

Q13. Why do we not see the shadow of a bird flying high in the sky but we do see it when the bird swoops low? The most likely reason is that when the bird is high

• A. the bird becomes transparent.
• B. the Sun shines from a different direction.
• C. the shadow on the ground is too faint and spread out to notice, but it becomes sharper as the bird nears the ground.
• D. no shadow forms because the bird is moving.

Q14. When Asha stands closer to a plane mirror, the image of her face

• A. becomes smaller.
• B. appears farther from the mirror.
• C. appears closer to the mirror.
• D. becomes laterally inverted only when she is close.

Q15. In Activity 11.2, a student looks at a lit candle through a long straight pipe and then through the same pipe after bending it. The student

• A. sees the flame in the straight pipe but not in the bent one.
• B. sees the flame in both cases.
• C. sees a brighter flame in the bent pipe.
• D. sees the flame only in the bent pipe.