DOWNLAOD THE ASSIGNMENT HERE:
https://www.sciencearena.in/p/education-resources.html
BIOLOGY TOPICS:
EUGLENA:
https://www.sciencearena.in/2025/05/euglena.html
MONOCYSTIS:
https://www.sciencearena.in/2025/05/monocystis.html
PARAMECIUM:
https://www.sciencearena.in/2025/05/paramecium.html
|
SCIENCE (X) LIGHT REFLECTION AND REFRACTION |
|
MULTIPLE CHOICE QUESTIONS (MCQs) |
|
1 |
The laws of reflection hold true
for (a) plane mirrors only (b) concave mirrors only (c) concave mirrors only (d) all reflecting surface |
1 |
|
2 |
A student wants to obtain an erect
image of an object using a concave mirrors of 10cm focal length. What will be
the distance of the object from mirrors ? (a) Less than 10 cm (b) 10 cm (c) between 10 cm and 20 cm (d) more than 20 cm. |
1 |
|
3 |
An optical device forms an erect image
of an object placed in fronts of it. If the image is one half that of the
object the optical device is a (a) concave mirrors (b)convex mirrors (c) plane mirrors (d) convex lens. |
1 |
|
4 |
The relation R=2f is valid (a) For concave mirrors but not for
convex mirrors (b) For convex mirrors but not for concave mirrors (c) neither for convex mirrors but not
for concave mirrors (d) for both concave and convex
mirrors |
1 |
|
5 |
In which of the following is a concave
mirrors used? (a) A solar cooker (b) A rear- view mirrors in vehicles (c) A safety mirrors in shopping malls
(d) In viewing full size image of
distant tall building |
1 |
|
6 |
The colour of light for which the
refractive index of glass is minimum, is (a)red (b) yellow (c) green (d) violet |
1 |
|
7 |
If a lens can converge the sun rays at
a point 20 cm away from its optical centre, the power of this lens is (a) +2D (b) -2D (c) +5D (d) -5D |
1 |
|
ASSERTION AND REASON QUESTIONS (a) Both Assertion (A) and Reason (R)
are true and Reason (R) is the correct explanation of the Assertion (A). (b) Both Assertion (A) and Reason (R)
are true and Reason (R) is not the correct explanation of the Assertion (A). (c) Assertion (A) is true, and Reason
(R) is false. (d) Assertion (A) is false, and Reason
(R) True. |
|
8 |
Assertion
(A): A concave lens of very short
focal length causes higher divergence than one with longer focal length. Reason
(R) : The power of a lens is
directly proportional to its focal length. |
1 |
|
9 |
Assertion
(A): The SI unit of power of lens
is ‘dioptre’. Reason
(R): The power of a concave lens is
positive and that of a convex lens is negative. |
1 |
|
10 |
Assertion
(A): A convex lens is made of two
different materials. A point object is placed on the principal axis. The
number of images formed by the lens will be two. Reason
(R): The image formed by convex
lens is always virtual. |
1 |
|
11 |
Assertion
(A): In the case of concave mirror,
the minimum distance between real object and its real image is zero. Reason
(R): If concave mirror forms
virtual image of real object, the image is magnified. |
1 |
|
VERY SHORT ANSWER QUESTIONS |
|
12 |
Name the type of mirrors used in the
design of solar furnaces. Explain how high temperature is achieved by this
device |
2 |
|
13 |
Draw a labelled ray diagram for the
image formation by a concave mirror when an object is placed between its
centre of curvature and focus. |
2 |
|
14 |
List four specific characteristics of
the images of the objects formed by convex mirrors. |
2 |
|
15 |
What is meant by power of a lens? What
does its sign (+ve or -ve) indicate? State its S.I. unit related to focal
length of a lens. |
2 |
|
16 |
State Snell's law of refraction of
light. Write an expression for the absolute refractive index of a medium in
terms of speed of light. |
2 |
|
SHORT ANSWER TYPE QUESTIONS |
|
17 |
A student has focused the image of an
object of case height 3 cm on a white screen using a concave mirror of focal
length 12 cm. If the distance of the object from the mirror is 18 cm, find
the values of the following: (i) distance of the image from the
mirror. (ii) height of the image. |
3 |
|
18 |
Draw ray diagrams for the following
cases when a ray of light: (i) passing through centre of
curvature of a concave mirror is incident on it. (ii) parallel to principal axis is
incident on convex mirror. (iii) is passing through focus of a
concave mirror incident on it |
3 |
|
19 |
Where should an object be placed in
front of a concave mirror of focal length 20 cm so as to obtain a two times
magnified virtual image of the object? |
3 |
|
20 |
How far should an object be placed
from a convex lens of focal length 20 cm to obtain its real image at a
distance of 30 cm from the lens? Determine the height of the image if the
object is 4 cm tall. |
3 |
|
21 |
An object of height 10 cm is placed 25
cm away from the optical centre of a converging lens of focal length 15 cm.
Calculate the image-distance and height of the image formed. |
3 |
|
22 |
Define power of a lens. The focal
length of a lens is-10 cm. Write the nature of the lens and find its power.
If an object is placed at a distance of 20 cm from the optical centre of this
lens, according to the New Cartesian Sign Convention, what will be the sign
of magnification in this case? |
3 |
|
23 |
An object is placed at a distance of
60 cm from a concave lens of focal length 30 cm. (i) Use lens formula to find the
distance of the image from the lens. (ii) List four characteristics of the
image (nature, position, size, erect/inverted) formed by the lens in this
case. (iii) Draw ray diagram to justify your
answer. |
3 |
|
LONG ANSWER TYPE QUESTIONS |
|
24 |
(a) If the image formed by a mirror
for all positions of the object placed in front of it is always diminished,
erect and virtual, state the type of the mirror and also draw a ray diagram
to justify your answer. Write one use such mirrors are put to and why? (b) Define the radius of curvature of
spherical mirrors. Find the nature and focal length of a spherical mirror
whose radius of curvature is +24 cm. |
5 |
|
25 |
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 in order to obtain a sharp image? (ii) Find the size of the image. (iii) Draw a ray diagram to show the
formation of image in this case. |
5 |
|
26 |
(i) Define principal axis of a lens.
Draw a ray diagram to show what happens when a ray of light parallel to the
principal axis of a concave lens passes through it. (ii) The focal length of a concave
lens is 20 cm. At what distance from the lens should a 5 cm tall object be
placed so that its image is formed at a distance of 15 cm from the lens? Also
calculate the size of the image formed |
5 |
|
27 |
(a) Define the following terms: (i) Power of lens (ii) Principal focus of a concave
mirror (b) Write the relationship among the
object distance (u), image distance (v) and the focal length (f) of a (i) Spherical lens (ii) Spherical mirror (c) An object is placed at a distance
of 10 cm from optical centre of a convex lens of focal length 15 cm. Draw a
labelled ray diagram to show the formation of image in this case. |
5 |
|
28 |
(a) State the laws of refraction of
light. (b) Explain the term absolute
refractive index of a medium and write an expression to relate it with the
speed of light. (c) The absolute refractive indices of
two media A and B are 2.0 and 1.5 respectively. If the speed of light in
medium B is 2×108 m/s. Calculate the speed of light in (i) vacuum (ii)
medium A |
5 |
|
CASE BASED STUDY QUESTIONS |
|
29 |
Read the given passage and answer the following questions: Ravi installed a large concave
mirror in his dressing room to observe his reflection. He noticed that when
he stood very close to the mirror, his image appeared erect and magnified.
However, as he moved farther, the image became inverted and smaller. 1. What kind of image is formed
when an object is placed very close to a concave mirror? 2. When Ravi moves away from the
mirror, what happens to the size and nature of the image? 3. At what position does a concave
mirror form a real, inverted and same-size image? 4. Write the mirror formula and
define each term. 5. Name one practical application
of a concave mirror based on this property. |
4 |
|
30 |
Read the given passage and answer the following questions: Meena placed a pencil in a glass
beaker filled with water and observed that the pencil appeared bent at the
water surface. Her teacher explained that this is due to refraction of light. 1. What is the reason for the
bending of the pencil in water? 2. Define refraction of light. 3. Name the laws of refraction. 4. If the light passes from air
(rarer medium) to water (denser medium), how does it bend? 5. Write the formula for the
refractive index and explain each term. |
4 |
|
31 |
Read the given passage and answer the following questions: An eye doctor uses a convex lens to
test a patient’s eyesight. The lens forms a real, inverted and diminished
image of a candle placed in front of it. 1. Which type of lens is used in
this case? 2. At what position is the object
placed in front of the convex lens to get a real, inverted and diminished
image? 3. Draw the ray diagram for the
above situation. 4. Define the lens formula. 5. State the sign conventions used
in lens formula. |
4 |
FOLLOW
THE INSTRUCTIONS FOR DOWNLOAD THIS ASSIGNMENT:
1. SEARCH WWW.SCIENCEARENA.IN
2. OPEN EDUCATION AND RESOURCES IN MENU BAR.
3. SINGLE CLICK DOWNLOAD AVAILABLE IN DOWNLAOD SECTION.
BIOLOGY TOPICS:
EUGLENA:
https://www.sciencearena.in/2025/05/euglena.html
MONOCYSTIS:
https://www.sciencearena.in/2025/05/monocystis.html
PARAMECIUM:
https://www.sciencearena.in/2025/05/paramecium.html