Questions · Page 4 of 6

M.C.Q. [I MARKS]

MCQ 1511 Mark
Which of the following prevents internal reflections of light inside the human eye?
  • A
    Iris
  • B
    Pupil
  • Choroid
  • D
    Blind spot
Answer
Correct option: C.
Choroid
The inner layer of the eye called the choroid is black. This prevents internal reflections of light inside the human eye.
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MCQ 1521 Mark
When a mirror is rotated through an angle $9$ the reflected ray from it, turns through an angle of:
  • A
    $\theta$
  • B
    $\frac{\theta}{2}$
  • $2\theta$
  • D
    $0$
Answer
Correct option: C.
$2\theta$
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MCQ 1531 Mark
The angle of reflection is equal to the angle of incidence:
  • Always.
  • B
    Sometimes.
  • C
    Under special conditions.
  • D
    Never.
Answer
Correct option: A.
Always.
The point at which the incident ray strikes the mirror is called the point of incidence. The angle of reflection is always equal to the angle of incidence.
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MCQ 1541 Mark
The human eye forms the image of an object at its:
  • A
    Cornea
  • B
    Iris
  • C
    Pupil
  • Retina
Answer
Correct option: D.
Retina
In the human eye, when the light rays enter to a sharp focusing point on the retina. It acts as the film on camera. It receives the image and passes to cornea. Here, the internal lens of the eyes is focused by cornea. It transforms this image falling on the lens into electrical impulses. The electrical impulses are transferred to optic nerves which carry information to brain and we can see the object.
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MCQ 1551 Mark
If the speed of red light is denoted by $\text{V}_\text{r}$, and the speed for violet light by $\text{V}_\text{u}$. Then in vacuum.
  • A
    $\text{V}_\text{r} >$ $\text{V}_\text{u}$
  • $\text{V}_\text{r} = \text{V}_\text{u}$
  • C
    $\text{V}_\text{r} < \text{V}_\text{u}$
  • D
    Both $1\ \&\ 3$
Answer
Correct option: B.
$\text{V}_\text{r} = \text{V}_\text{u}$
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MCQ 1561 Mark
A simple magnifying glass consists of a.
  • A
    Convex lens.
  • B
    A concave lens.
  • Convex lens of small focal length.
  • D
    Convex lens of large focal length.
Answer
Correct option: C.
Convex lens of small focal length.
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MCQ 1571 Mark
The Kaleidoscope is an instrument consisting of plane mirrors that produces multiple reflections of colored glass pieces and create beautiful pattern. It consists of three long and narrow strips of plane mirrors. The angle of inclination of the mirror is $............$
  • A
    $30^\circ$
  • $60^\circ$
  • C
    $90^\circ$
  • D
    $120^\circ$
Answer
Correct option: B.
$60^\circ$
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MCQ 1581 Mark
Boojho is doing his homework which is given by his teacher. Would you help him to choose the correct sentences?
  • A
    The incident ray, the reflected ray and the normal, all lie in the same plane.
  • B
    The angle of reflection is always equal to the angle of incidence.
  • C
    If we change the angle of incidence, the angle of reflection will also change accordingly.
  • All the above.
Answer
Correct option: D.
All the above.
Here, all the statements are correct.
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MCQ 1591 Mark
Type of mirror used as side view mirror is:
  • Convex mirror
  • B
    Plane mirror
  • C
    Concave mirror
  • D
    Ground mirror
Answer
Correct option: A.
Convex mirror
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MCQ 1601 Mark
Which of the following part of eye controls the amount of light entering the eye by contracting or dilating?
  • A
    Retina
  • B
    Cornea
  • C
    Pupil
  • Iris
Answer
Correct option: D.
Iris
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MCQ 1611 Mark
How is a rainbow formed?
  • A
    When raindrops absorb sunlight.
  • B
    When raindrops reflect sunlight.
  • When raindrops disperse sunlight.
  • D
    When raindrops diffract sunlight.
Answer
Correct option: C.
When raindrops disperse sunlight.
The dispersion of sunlight is the splitting of white light into rays of seven different colours. Just after the rain, there are a large number of water drops in the air which act like small prisms. As the white sunlight enters these water drops, the constituents of white light of different colours are refracted by different amounts, and a band of seven colours called rainbow is formed.
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MCQ 1621 Mark
The change in focal length of an eye lens is caused by the action of the?
  • A
    Pupil
  • B
    Retina
  • Ciliary muscles
  • D
    Iris
Answer
Correct option: C.
Ciliary muscles
The relaxation or contraction of ciliary muscles changes the curvature of the eye lens. The change in curvature of the eye lens changes the focal length of the eyes. Hence, the change in focal length of an eye lens is caused by the action of ciliary muscles.
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MCQ 1631 Mark
Which of the following statement is or are correct?
  • A
    Light is a form of energy.
  • B
    Light is needed to see things around us.
  • C
    We cannot see objects in a dark room or in the darkness of light even when our eyes are wide open.
  • All the above.
Answer
Correct option: D.
All the above.
Here, all the statements are correct.
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MCQ 1641 Mark
How many images will be formed when two plane mirrors are placed parallel to each other?
  • A
    Two
  • Infinite
  • C
    One
  • D
    Four
Answer
Correct option: B.
Infinite
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MCQ 1651 Mark
The focal length of concave mirror is $-40\ cm$. Its radius of curvature is.
  • A
    $-20\ cm$
  • B
    $+20\ cf$
  • $-80\ cm$
  • D
    $+80\ cm$
Answer
Correct option: C.
$-80\ cm$
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MCQ 1661 Mark
The number of images observable between two parallel mirrors is:
  • A
    $12$
  • B
    $4$
  • C
    $16$
  • Infinite
Answer
Correct option: D.
Infinite
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MCQ 1681 Mark
Velocity of light in vacuum is.
  • A
    $13 \times 10^6\ m/ s$
  • B
    $3 \times 10^{10}\ m/ s$
  • $3 \times 10^{8}\ m/ s$
  • D
    $3 \times 10^{5}\ m/ s$
Answer
Correct option: C.
$3 \times 10^{8}\ m/ s$
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MCQ 1691 Mark
Image formed by the plane mirror is:
  • A
    Always real.
  • Always virtual.
  • C
    Sometimes real sometimes virtual.
  • D
    None of these
Answer
Correct option: B.
Always virtual.
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MCQ 1701 Mark
The light appears to travel in straight line because.
  • A
    It consists of small particles.
  • B
    The velocity of light is very large.
  • The wavelength of light is very small.
  • D
    Light is reflected by surroundings.
Answer
Correct option: C.
The wavelength of light is very small.
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MCQ 1711 Mark
Match the column $I$ with column $II$ and column $III$ and select correct option from the codes given below. $($Note: These columns are for convex lens$).$
 
Column $I$
$($Position of the object$)$
 
Column $II$
$($Position of the image$)$
 
Column $III$
$($Type of Image$)$
$(a)$
Object beyond $2F$
$(i)$
At $2F$
$(p)$
Real, inverted, large
$(b)$
Object at $2F$
$(ii)$
Same side as the object
$(q)$
Virtual, erect, magnified
$(c)$
Object between $F$ and $2F$
$(iii)$
Beyond $2F$
$(r)$
Real, inverted, same size
$(d)$
Object within the focal length
$(iv)$
Between $F$ and $2F$
$(s)$
Real, inverted, diminished
  • A
    $(a)-(ii)-(p);$
    $(b)-(iii)-(q);$
    $(c)-(iv)-(r);$
    $(d)-(i)-(s)$
  • $(a)-(iv)-(s);$
    $(b)-(i)-(r);$
    $(c)-(iii)-(p);$
    $(d)-(ii)-(q)$
  • C
    $(a)-(iii)-(q);$
    $(b)-(ii)-(s);$
    $(c)-(ii)-(r);$
    $(d)-(iii)-(p)$
  • D
    $(a)-(i)-(r);$
    $(b)-(iv)-(p);$
    $(c)-(i)-(s);$
    $(d)-(iv)-(q)$
Answer
Correct option: B.
$(a)-(iv)-(s);$
$(b)-(i)-(r);$
$(c)-(iii)-(p);$
$(d)-(ii)-(q)$
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MCQ 1721 Mark
We can see a non$-$luminous object when the light:
  • A
    Emitted by the object falls on the eye.
  • Is reflected from the object towards our eye.
  • C
    Completely passes through the object.
  • D
    Gets completely absorbed by the object.
Answer
Correct option: B.
Is reflected from the object towards our eye.
We can see a non$-$luminous object $($object that does not produce its own light$)$, when light reflected by the object enters our eyes.
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MCQ 1731 Mark
Statement $I:$ A school girl wears a school uniform of length $1m.$ She requires a mirror of length $0.5m$ fixed on the vertical wall to see her uniform in the mirror.
Statement $II:$ The minimum height of the mirror to be required to see the full image of man of height $h$ is $h/ 2.$
  • Both Statements are true, Statement$-II$ is the correct explanation of Statement$-I$.
  • B
    Both Statements are true, Statement$-II$ is not correct explanation of Statement$-I.$
  • C
    Statement$-I$ is true, Statement$-II$ is false.
  • D
    Statement$-I$ is false. Statement$-II$ is true.
Answer
Correct option: A.
Both Statements are true, Statement$-II$ is the correct explanation of Statement$-I$.
Both Statements are true, Statement$-II$ is the correct explanation of Statement$-I.$
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MCQ 1741 Mark
The angle of incidence is always $............$ to theangle of reflection.
  • A
    Greater
  • B
    Smaller
  • Equal
  • D
    None of these
Answer
Correct option: C.
Equal
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MCQ 1751 Mark
If two plane mirrors are inclined at an angle of $90^\circ$ to each other, how many images of an object are seen$?$
  • A
    Only $1$
  • B
    Only $2$
  • Only $3$
  • D
    Any of $1, 2, 3$ or $4$ depending on the position of observer and object.
Answer
Correct option: C.
Only $3$
 Number of image $ =\frac{360^\circ}{\theta} - 1=\frac{360^\circ}{90^\circ}-1$
$=4-1=3$
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MCQ 1761 Mark
Statement $I:$ When a light ray from rarer medium is refracted into denser medium its velocity decreases and wavelength decreases.
Statement $II:$ Refractive index decreases with increases in temperature.
  • A
    Both Statements are true. Statement$-II$ is the correct explanation of Statement$-I.$
  • Both Statements are true. Statement$-II$ is not correct explanation of Statement$-I$.
  • C
    Statement$-I$ is true, Statement$-II$ is false.
  • D
    Statement$-I$ is false. Statement$-II$ is true.
Answer
Correct option: B.
Both Statements are true. Statement$-II$ is not correct explanation of Statement$-I$.
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MCQ 1771 Mark
A ray of light is incident on a concave lens parallel to its principal axis. The path of the refracted ray is correctly depicted by:
  • A
  • C
  • D
Answer
Correct option: B.
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MCQ 1781 Mark
A layered lens as shown in the figure is made of two materials indicated by different shades. A point object is placed on its axis. The lens will form.
  • A
    One image
  • Two images
  • C
    Five images
  • D
    Three images
Answer
Correct option: B.
Two images
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MCQ 1791 Mark
A double convex air bubble in water would behave as a.
  • A
    Convergent lens
  • B
    Circle
  • Divergent lens
  • D
    Pane mirror
Answer
Correct option: C.
Divergent lens
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MCQ 1801 Mark
The image formed by a convex mirror of real object is larger than the object.
  • A
    When $u < 2f$
  • B
    When $u > 2f$
  • C
    For all values of $u$
  • For no value of $u$
Answer
Correct option: D.
For no value of $u$

Whatever may be the position of object, a convex mirror always forms a virtual, erect and diminished image.

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MCQ 1811 Mark
If the radius of curvature of a concave mirror is $R,$ its focal length is.
  • A
    $2R$
  • B
    $R$
  • $\frac{\text{R}}{2}$
  • D
    $\frac{2}{\text{R}}$
Answer
Correct option: C.
$\frac{\text{R}}{2}$
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MCQ 1821 Mark
The focal length of the eye lens is adjusted by the.
  • A
    Vitreous humour
  • B
    Aqueous humour
  • Ciliary muscles
  • D
    Optic nerves
Answer
Correct option: C.
Ciliary muscles
In the human eye, the ciliary muscles are attached with the eye lens. These muscles on contracting or relaxing make the eye lens thin or thick respectively. The focal length of the eye lens also changes with its thickness.
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MCQ 1831 Mark
The angle of incidence is the angle made by the incident ray with:
  • A
    The surface.
  • Normal to the surface.
  • C
    The reflected ray.
  • D
    The refracted ray.
Answer
Correct option: B.
Normal to the surface.
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MCQ 1841 Mark
An object placed $4\ m$ from a plane mirror 'Br is shifted by $0.5\ m$ away from the mirror. What is the distance between the object and its image?
  • A
    $4\ m$
  • B
    $3.5\ m$
  • $9\ m$
  • D
    $5\ m$
Answer
Correct option: C.
$9\ m$

 Object distance after shifting the object $= 4\ m + 0.5 \ m = 4.5\ m$ For a plane mirror;
Object distance = Image distance $= 4.5  \ m$
Distance between the object and its image $= 4.5 + 4.5 = 9\ m.$

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MCQ 1851 Mark
A person cannot see the distant objects clearly $($though he can see the nearby objects clearly$)$. He is suffering from the defect of vision called:
  • A
    Hypermetropia.
  • Myopia.
  • C
    Night blindness.
  • D
    Cataract.
Answer
Correct option: B.
Myopia.
Myopia is the defect of vision wherein a person cannot see the distant objects clearly as the light is unable to focus on the retina and thus distant objects appear to be blurred.
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MCQ 1861 Mark
Shyam views a certain object and finds that it is not properly visible to him. The image of the said object is formed by his eye lens $3\ cm$ away from the pupil of his eye. Shyam can correct the defect in his vision by using:
  • Convex lens
  • B
    Bifocal lens
  • C
    Concave lens
  • D
    Cylindrical lens
Answer
Correct option: A.
Convex lens

 The diameter of the eye ball is approximately $2.3\ cm.$
Images are formed on the retina of the normal eye, which is approximately $2.3\ cm$ behind the pupil.The formation of an image $3\ cm$ away from the pupil of the eye indicates that the light rays are focused behind the retina. For proper visibility, the light rays must focus on the retina.

It can be concluded that Shyam is suffering from hypermetropia and a convex lens can be used to correct this defect.

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MCQ 1871 Mark
In the retina of the eye, the area having no sensory cells is called.
  • A
    Iris
  • Blind spot
  • C
    cornea
  • D
    Dark spot
Answer
Correct option: B.
Blind spot
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MCQ 1881 Mark
Which of the following is used by $E.N.T.$ doctors$?$
  • A
    Convex mirror
  • B
    Convex lens
  • C
    Plane mirror
  • Concave mirror
Answer
Correct option: D.
Concave mirror

A concave mirror is used by $E.N.T.$ doctors to get a magnified image of internal organs like ear, nose and throat.

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MCQ 1891 Mark
Maximum part of light is reflected by:
  • Opaque object
  • B
    Translucent object
  • C
    Transparent object
  • D
    All of these
Answer
Correct option: A.
Opaque object
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MCQ 1901 Mark
The two lens of different power are given as shown below in the figure.

When both the lens is placed in contact with each other, the focal length of the combined lens is:
  • A
    $20$ diopter
  • B
    $22$ diopter
  • $24$ diopter
  • D
    $16 $ diopter
Answer
Correct option: C.
$24$ diopter
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MCQ 1911 Mark
A thin lens produces an image of the same size as the object. Then from the optical centre of the lens, the distance of the object is.
  • A
    Zero
  • B
    $4f$
  • $2f$
  • D
    $\frac{\text{f}}{2}$
Answer
Correct option: C.
$2f$
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MCQ 1921 Mark
The image formed by the eye lens on the retina is.
  • A
    Real, inverted, and large.
  • B
    Virtual, erect, and large.
  • Real, inverted, and diminished.
  • D
    Virtual, erect, and diminished.
Answer
Correct option: C.
Real, inverted, and diminished.
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MCQ 1941 Mark
We can see ourselves in mirror or polished surface but not on walls because the reflection from walls is:
  • A
    Regular reflection.
  • B
    Normal reflection.
  • Irregular reflection.
  • D
    Specular reflection.
Answer
Correct option: C.
Irregular reflection.
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MCQ 1951 Mark
Which of the following letters will be seen without any change in a plane mirror$?$
  • A
    $S$
  • $T$
  • C
    $L$
  • D
    $P$
Answer
Correct option: B.
$T$

$ T$ is a laterally symmetrical object and hence its image in a plane mirror would be the same as itself.

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MCQ 1961 Mark
Consider the following statements and select the option which correctly identifies true $(T)$ and false $(F).$
$i.$ Part that gives colour to the eye is iris.
$ii.$ Transparent outer layer that refracts light is lens.
$iii.$ Retina is a light sensitive layer of the eye.
$iv.$ Cornea is a region without any sensory cell
  • A
    $\begin{array}{|c|c|c|c|}
    \hline \text { (i) } & \text { (ii) } & \text { (iii) } & \text { (iv) } \\
    \hline F & T & F & T \\
    \hline
    \end{array}$
  • B
    $\begin{array}{|c|c|c|c|}
    \hline \text { (i) } & \text { (ii) } & \text { (iii) } & \text { (iv) } \\
    \hline T & F & T & T \\
    \hline
    \end{array}$
  • C
    $\begin{array}{|c|c|c|c|}
    \hline \text { (i) } & \text { (ii) } & \text { (iii) } & \text { (iv) } \\
    \hline T & T & F & F \\
    \hline
    \end{array}$
  • $\begin{array}{|c|c|c|c|}
    \hline \text { (i) } & \text { (ii) } & \text { (iii) } & \text { (iv) } \\
    \hline F & F & T & T \\
    \hline
    \end{array}$
Answer
Correct option: D.
$\begin{array}{|c|c|c|c|}
\hline \text { (i) } & \text { (ii) } & \text { (iii) } & \text { (iv) } \\
\hline F & F & T & T \\
\hline
\end{array}$
Most of the refraction occurs in cornea. Cornea is a region without sensory cells. It is transparent and allows the light to enter the eye. Part that gives colour to the eyes is retina.
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MCQ 1971 Mark
The image formed by a plane mirror is:
  • A
    Virtual, behind the mirror and enlarged.
  • Virtual, behind the mirror and of the same size as the object.
  • C
    Real, at the surface of the mirror and enlarged.
  • D
    Real, behind the mirror and of the same size as the object.
Answer
Correct option: B.
Virtual, behind the mirror and of the same size as the object.
The images formed by a plane mirror are virtual, opposite in direction and are of the same size as the object.
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MCQ 1981 Mark
Which of the following is a non-luminous object?
  • A
    Sun
  • B
    Star
  • Moon
  • D
    Fire
Answer
Correct option: C.
Moon
The objects which do not emit their own light are called “non luminous” objects. Actually, the moon the non-luminous objects cannot make their own light. The moon, earth, table, chair, book, trees, plants, flowers, human beings, mirror, diamond are some of the examples of non-luminous objects.
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MCQ 1991 Mark
Two mirrors $A$ and $B$ are placed at right angles to each other as shown in the figure.

A ray of light incident on mirror $A$ at an angle of $25^\circ $ falls on mirror $B$ after reflection. The angle of reflection for the ray reflected from mirror $B$ would be:
  • A
    $25^\circ .$
  • B
    $50^\circ .$
  • $65^\circ .$
  • D
    $115^\circ .$
Answer
Correct option: C.
$65^\circ .$
Angle of reflection for the ray reflected from mirror $B$ will be $65^\circ $ because figure below shows how reflected ray from mirror A forms incident ray on mirror 6 and then reflected back by an angle of $65^\circ .$
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M.C.Q. [I MARKS] - Page 4 - Science STD 8 Questions - Vidyadip