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.
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, ______ and ________
Crossword Puzzle
Across
4. A convex lens is _____ lens
6. An image which can be obtained on a screen
Down
1. A concave lens is _____ lens
2. An image which cannot be obtained on a screen
3. Any polished or a shining surface acts as a _______
5. One of the rainbows colours
An image that cannot be obtained on a screen is called …………………. .
2. Image formed by a convex …………….. is always virtual and smaller in size.
3. An image formed by a ………………. mirror is always of the same size as that of the object.
4. An image which can be obtained on a screen is called a ………………. image.
5. An image formed by a concave ………………… cannot be obtained on a screen.
B. State ‘True’ or ‘False’:
1. We can obtain an enlarged and erect image by a convex mirror. ………………..
2. A concave lens always forms a virtual image. …………………
3. We can obtain a real, enlarged and inverted image by a concave mirror. ………………..
4. A real image cannot be obtained on a screen. ………………….
5. A concave mirror always forms a real image. …………………..
C. Match the following:
‘A’
‘B’
1. A plane mirror
a. Used as a magnifying glass.
2. A convex mirror
b. Can form image of objects spread over a large area.
3. A convex lens
c. Used by dentists to see enlarged image of teeth.
4. A concave mirror
d. The image is always inverted and magnified.
5. A concave lens
e. The image is erect and of the same size as the object.
f. The image is erect and smaller in size than the object.
Answers
Answer:
a. The property by which light in the straight line is termed as Rectilinear propagation
b. Light travels with a speed of 299.708 km/s in air.
c. The splitting of white light into its seven constituent colours is called dispersion of light.
d. splitting of white light is the study of spectrum formed when a surface emits light.
e. Isaac Newton was the first person who discovered that sunlight is made up of seven colours.
f. convex lens is present in human eye.
g. A concave lens always forms an erect, virtual and diminished image.
True and false
a. Light is the fastest travelling form of energy True
b. Light travels in curve path false
c. As per law of reflection, Angle of Incidence = Angle of Reflections True
d. A concave lens can be used to produce an enlarged and erect image False
e. An object can be seen only if it emits light False
f. A concave lens is called the converging lens False
Question 4
Fill in the blanks
a. The inner surface of a spoon acts like a concave mirror while its outer surface acts like a convex mirror
b. An image formed on a screen is called a Real image.
c. convex mirrors used as side mirrors in scooters /cars
d. The lenses which feel thicker in the middle than at the edges are convex lens
e. The seven colours in rainbow are red, orange, yellow, green, blue, Indigo and violet.
1. A concave lens is biconvex lens
2. An image which cannot be obtained on a screen a virtual image.
3. Any polished or a shining surface acts as a mirror .
1.An image that cannot be obtained on a screen is called. virtual image.
2. Image formed by a convex mirror is always virtual and smaller in size.
3. An image formed by a plane mirror is always of the same size as that of the object.
4. An image which can be obtained on a screen is called a real image.
5. An image formed by a concave lens cannot be obtained on a screen.
B. State ‘True’ or ‘False’:
1. We can obtain an enlarged and erect image by a convex mirror. false
Explanation:
Image formed by a convex mirror is always diminished and erect.
Explanation:
2. A concave lens always forms a virtual image.True
3. We can obtain a real, enlarged and inverted image by a concave mirror. True
4. A real image cannot be obtained on a screen.False
Explanation:
A real image is always obtained on a screen
5. A concave mirror always forms a real image.False
Explanation:
Concave mirrors can form both real and virtual images.
Question 3.
Match the columns:
Column 1 Column 2
(a) A plane mirror (i) used as a
magnifying glass.
(b) A convex mirror (ii) can form image of
objects spread over a
large area.
(c)A convex lens (iii) used by dentists to
see enlarged image
of teeth.
(d)A Concave mirror (iv) the image formed
is always inverted and
magnified.
(e) A Concave lens (v) the image is erect
and of the same size as
the object.
(vi) The image is erect.
and smaller.
Answer:
(a) A plane mirror (v) the image is erect and of
the same size as the object.
(b) A convex mirror (ii) Can form image of objects
spread over a large area.
(vi) The image is erect.
and smaller in size than.
the object.
(c) A convex lens (i) Used as a magnifying glass.
(d) A concave mirror. (iii) Used by dentists to see
enlarged image of teeth.
(e) A concave lens (vi) The image is erect and
smaller in size than the
object.