Propagation of Light

Q. An object is moving with velocity v towards a stationary plane mirror. If mirror starts moving towards the object with speed v, the speed of the image of the object

1. Will remain unchanged
2. Will decrease
3. Will increase
4. May remain unchanged

Q.

Which property of light makes a pencil cast a shadow when it is held in front of a light source ?

Q. A boy is standing in front of a straight plane mirror. His uncle is standing behind him as shown. The height of the boy is 3 feet and that of the uncle is 6 feet. What is the minimum length of the mirror required so that the boy can completely see his uncle’s image in the mirror?

1. 1 feet
2. 2 feet
3. $\frac{1}{2}$ feet
4. $\frac{3}{4}$ feet

Q. Which of the following mirrors is used to make a periscope?

1. Concave mirror
2. Convex mirror
3. Plane mirror
4. Cylinderical mirror

Q.

A circular object when kept between a small source of light and a screen, casts a sharp shadow on the screen.

This experiment proves:

1. Rectilinear propagation of light

2. Laws of reflection

3. Wave nature of light

4. Laws of refraction

Q.

If a material possesses relative permittivity $3$ and relative permeability $\frac{4}{3}$ for a given wavelength, the critical angle for that wavelength is.

1. $15°$

2. $30°$

3. $45°$

4. $60°$

Q.

Discuss the uses of a periscope.

Q. Light travels in because it is the only path between two points.

1. straight lines
2. longest
3. quickest
4. waves
5. shortest

Q. As shown in the diagram, the light ray is approaching the first mirror at an angle of 45° with the mirror surface. How many times will the ray reflect before it exits the system?

1. 3
2. 2
3. 4
4. Infinitely many

Q. An object 4.0 cm in size, is placed 25.0 cm in front of a concave mirror of focal length 15.0 cm.
(i) At what distance from the mirror should a screen be placed to obtain a sharp image?
(ii) Find the size of the image.
(iii) Draw a ray diagram to show the formation of the image in this case.

Q. A dentist uses a small concave mirror of focal length 3 cm and hold it at a distance of 2 cm from the tooth. Which of the following statement is incorrect about the image formed?

Q. How does the sharp edges of shadow shows that light travels or propagates in a straight line?

Q. Which of the following mirrors is used to make a periscope?

1. Convex mirror
2. Concave mirror
3. Plane mirror
4. Cylinderical mirror

Q. Light can travel in a curved path.

1. True
2. False

Q.

The clarity and length of shadow depends on the ________ of the light source.

Q. Which property of light makes a pencil cast a shadow when it is held in front of a light source?

Q. The distance between the object and the image from a plane mirror will always be in the ratio _____________.

Q.

In a cinema hall, the movie we see is a image.

1. real
2. painted
3. virtual

Q. Light travels in because it is the only path between two points.

1. straight lines
2. longest
3. quickest
4. circular
5. shortest

Q. Light follows rectilinear propagation in a given medium.

1. True
2. False

Q. Rohan is in front of a plane mirror. Determine the shift in position of the image if both Rohan and the mirror are moved 5 m each towards each other.

1. 5 m
2. 15 m
3. 10 m
4. 20 m

Q.

Light always travels along a

1. Curved path

2. Zigzag path

3. Straight line path

4. Circular path

Q. In a uniform medium, light travels in a straight line.

1. True
2. False

Q. The reflection in which the incident light scatters in many directions is known as:

1. Diffused reflection
2. Regular reflection
3. Normal reflection
4. Unnatural reflection

Q. The laws of reflection are invalid in case of diffused reflection.

1. False
2. True

Q.

Light ray travels in a

1. circular-motion

2. parabolic motion

3. straight line

4. elliptical path

Q.

how the formation of shadow of an opaque object points to the straight line path of light

Q. Find the right sequence of things that happen in the process of seeing an object.

1. Brain
2. Object
3. Eyes
4. Reflection
5. Light source

Q. The shape of the shadow formed is same as that of the object implies that light travels in a _____ path.

1. straight
2. spiral
3. zigzag
4. curved