Shadow

Q.

What do you understand by the term optical medium? What are its kinds? Give two examples of each kind.

Q. Write the differences between umbra and penumbra. [3 MARKS]

Q. What is a shadow?

Q. What will be shape of the shadow on the screen? (Note that the cylinder is an opaque object)

1. Circle
2. Rectangle
3. Vertical line
4. Ellipse

Q. What happens to the shadow if the torch is moved away from the object?

1. It decreases in size.
2. No change would be observed.
3. It increases in size.
4. Its shape changes into a rectangle.

Q.

When the distance between the object and the screen is increased

Q. When an object moves closer to a light source, its shadow gets

1. bigger
2. smaller
3. diminished

Q. Which of the following can create a shadow when light falls on them?

1. Mirror
2. Transparent objects
3. Glass sheet
4. Opaque objects

Q.

Which shape will you use to create a circular shadow, if a torch is held in one way and rectangular shadow if the torch is held in another way? [3 MARKS]

Q.
Study the above figure. In both the cases A and B, the shape of the shadow formed on the screen will be same.

1. True
2. False

Q.

When an object obstructs the path of light, the dark area formed on the screen is called________.

1. shadow

2. mirage

3. image

4. reflection

Q.

Shadow is a dark outline of an _____ body placed in the path of light.

Q. When placed in between a source of light and a screen, a clear glass sheet can form its shadow.

1. True
2. False

Q. Three torches A, B and C shown in figure are switched on one by one. The shadow of the ball will not be casted, when __________is/are switched on.

1. torch A
2. torch B
3. torch C
4. both torch A and torch B

Q. A shadow will be formed by a square pyramid which is made of clear glass.

1. True
2. False

Q. A region of darkness formed on a screen when an opaque object blocks the path of light is called .

1. luminosity
2. reflection
3. shadow

Q.

Do the shadows look different when the colours of the objects are different?

Q. A relatively darker patch was observed below a football when kept under the sunlight. This patch is called as a ________.

1. dim image
2. clear image
3. shadow
4. blurred image

Q. When an object is placed _____ a light source, the shadow formed on the screen is _______. ​

1. closer to, smaller​
2. closer to, bigger​
3. far from, of the same size​
4. far from, bigger​

Q. The size of a shadow will ______ if an object is moved away from a light source keeping the positions of the source and the screen fixed.​​

Q. Which among the following instrument is used to know time?

1. Pinhole camera
2. Sundial
3. Measuring tape
4. Scale

Q.

As we move a body away from the torch light towards the screen, its image size _______.

1. decreases

2. increases

3. increases then decreases

4. remains same

Q. In the given scenario, identify the source and screen for the shadow of the flag.

1. Source: Flag, Screen: Sun
2. Source: Sun, Screen: Flag
3. Source: Flag, Screen: Land
4. Source: Sun, Screen: Land

Q.

Shadows appear to be black in colour. Which of the following reasons attribute to this?

1. Both B & C

2. Because no light reaches on screen in area where shadow form

3. The colour of object is colour components of light that reflect

4. In Sunlight, the object becomes black

Q. A dark patch was observed behind a football when kept in the sunlight. This patch is better called as:

1. duplicate image

2. clear image

3. shadow

4. blurred image

Q. In an experiment, positions of light source and screen are fixed. An opaque object is taken closer to the source then the size of the shadow on the screen ___________.

1. will increase
2. will decrease
3. cannot be predicted
4. will remain same

Q. What is the colour of the shadow formed, when red light hits a piece of white chalk?​

1. White​
2. Black​
3. Red​
4. Green​

Q. The given figure shows the formation of the shadow of an opaque object when light from a torch strikes the object. If the distance between the torch and the object is increased, the size of the shadow will:

1. Decrease
2. Increase
3. Remains same
4. None of these

Q. Which of the following arrangements could practically result in an eclipse visible from Earth?

1. $\text{Earth}-\text{Sun}-\text{Moon}$
2. $\text{Earth}-\text{Moon}-\text{Sun}$
3. $\text{Moon}-\text{Earth}-\text{Sun}$
4. $\text{Moon}-\text{Sun}-\text{Earth}$

1. Only 1 and 4
2. All of them
3. Only 1, 3, and 4
4. Only 2 and 3

Q. A student obtains a shadow of an opaque object using a red, and then a green flashlight. The colour of the shadow will be different for each case.

1. True
2. False