WORKSHEET CHAPTER: LIGHT CLASS VII Question 1 Fill the blanks: a. The property by which light in the straight line is termed as_______________________ b. Light travels with a speed of ______________________________km/s in air. c. The splitting of white light into its seven constituent colours is called________________ d. _____________________is the study of spectrum formed when a surface emits light. e. _____________________was the first person who discovered that sunlight is made up of seven colours. f. _____________________lens is present in human eye. g. A ____________________ lens always forms an erect, virtual and diminished image. Question 2 Answer the following questions – i. Differentiate between the following (3 points each) a) concave and convex mirror. b) Real and virtual image. i. Define a) Mirror b) lens c) prism d) rainbow e) lateral inversion ii. Which mirror is used as rear views mirror and why? iii. Why is it dangerous to look at the sun through a convex lens? iv. What is a Newton’s disc? How does it show that light is composed of many colours? v. Why is concave mirror used in search lights & head lights? Question 3 True and false a. Light is the fastest travelling form of energy b. Light travels in curve path c. As per law of reflection, Angle of Incidence = Angle of Reflections d. A concave lens can be used to produce an enlarged and erect image. e. An object can be seen only if it emits light f. A concave lens is called the converging lens Question 4 Fill in the blanks a. The inner surface of a spoon acts like a ________ while its outer surface acts like a _________________ b. An image formed on a screen is called a _______ c. _______mirrors used as side mirrors in scooters /cars d. The lenses which feel thicker in the middle than at the edges are _________ e. The seven colours in rainbow are red, orange, yellow, green, blue
Answers
Answer:
a.) rectilinear propagation light I attached photo to rectilinear propagation of light n next b.)300,000 km/ sec(186 miles/sec) again I gave pic see and c )ligth dispersion if turn beside ok pics you can see explaination isaac network discover ed sunlight and other I don't know sorry dear ask other please I gave with explain n definition by pictures see. sorry
Answer:
Q.1
a. Rectilinear propagation of light.
b. 3,00,000 km/s
c. dispersion of white light.
d. Splitting of white light
e. Issac Newton
f. Convex
g. concave
Q.2
i. a) A concave mirror is a spherical mirror with an inwardly curved reflection surface, whereas a convex mirror is a spherical mirror with an outwardly bulged reflecting surface.
b) A real image is the image which is obtained on a surface or a screen, whereas a virtual image is the image which isn't obtained on a screen.
i. a) A mirror is an object in which we can view ourselves.
b) A lens is a transparent material which refracts light.
c) A prism is a transparent, polished flat optical element on which light reflects.
d) A rainbow is a multicolored arc made by light striking water droplets.
e)Lateral inversion is the reversal of mirror image where the right side of the object appears on the left side behind the mirror.
ii. Convex mirrors are used as rear-view mirrors in motor vehicles because they form virtual, erect and diminished images irrespective of distances of the object.
iii. A convex lens can focus the sun light to a point to such an intensity which can burn paper, wood, plastic etc. This intense light can easily damage and distort our eye lens. So, it is dangerous to look at the sun through a convex lens.
iv. A Newton disc is a disc with segments in rainbow colours. When the disc is rotated, the colors fade to white; In this way Isaac Newton demonstrated that white light is a combination of the seven different colours found in a rainbow.
v. Concave mirror is used in headlights of vehicles, because when the bulb of headlight is placed at focus of concave mirror, it allows the light to spread out to infinity.
Q.3
a) True
b) True
c) True
d) False
e) True
Q.4
a) concave mirror.
b) real image.
c) Convex
d) convex lens.
e) (VIBGYOR) violet, indigo, blue, green, yellow, orange and red.
Explanation:
Q.3
b) light rays passing near very massive objects such as stars are seen to travel in curved path.
d) A concave lens can produce erect, diminished and virtual image. NOT enlarged image.