Question 1 :
On the basis of their experiment, "To trace the path of a ray of light through a rectangular glass slab," students of a class arrived at which one of the following conclusions :
Question 3 :
State the direction of incident ray which after reflection from a spherical mirror retraces its path:
Question 4 :
If the refractive index of medium $b$ with respect to medium $a$ and that of medium $c$ with respect to medium b are given, then the refractive index of a medium $c$ with respect to a medium $a$ can be found by using the relation<br/>$n_{ca}\, =\, n_{ba}\, \times\, ........$<br/><br/>
Question 5 :
Object when placed at ________ in front of concave mirror magnification of -1 is obtained.
Question 6 :
A convex lens makes a real image $4\ cm$ long on a screen. When the lens is shifted to a new position without disturbing the object, we again get a real image on the screen which is $16\ cm$ tall. The length of the object must be
Question 7 :
The image formed by the given convex mirror when it is inside focal distance is:
Question 8 :
What is the power of the lens, if the far point of a short sighted eye is $200\ cm$?
Question 12 :
A thin convex lens of focal length $10\ cm$ is placed in contact with a concave lens of same material and of same focal length. he focal length of combination will be
Question 14 :
A person sees his virtual image by holding a mirror very close to the face. When he moves the mirror away from his face, the imagebecomes inverted. What type of mirror he is using
Question 16 :
The focal length of a concave lens is $2m$. Then the power of the lens is:<br/>
Question 17 :
The focal length of convex lens is 30 cm and the size of image is quarter of the object, then the object distance is:-
Question 18 :
A wave has velocity v in medium P and velocity 2v in medium Q. If the wave is incident in medium P at an angle of 30, then the angle of refraction will be
Question 19 :
Various optical instruments like telescopes, microscopes, camera uses which property of light?<br>
Question 20 :
Two thin lenses of focal lengths $f_{1} and f_{2}$ are in contact and coaxial. The power of the combination is :<br/>
Question 21 :
A beam of light passing from air enters into the glass. Identify which of the following statements is true?<br/>
Question 22 :
Light moves from air into water. The light makes an angle of $47^{\circ}$ with the normal in the air. What angle will it make with the normal in the water?<br>The index of refraction for air is $1.00$.<br>The index of refraction for water is $1.33$
Question 23 :
The power of a lens having a focal length of $1 cm$ is :<br/>
Question 24 :
A ray of light passing through the focus of a concave mirror will be :
Question 25 :
An object 20 cm from lens, has a virtual image at 10 cm from the object. The power of the lens is
Question 27 :
The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
Question 28 :
The heat of sun focussed by a convex lens on a piece of paper is capable of
Question 29 :
A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see:
Question 32 :
The ratio of the size of the image to the size of the object is known as
Question 33 :
No matter where the object is placed in front of a mirror, the image formed is virtual, erect and smaller than the object. This mirror must be:
Question 34 :
The relation among $u$, $v$ and $f$ for a mirror is:
Question 36 :
Which of the following is not a characteristic of the image formed by Convex lens ?
Question 37 :
In case of a virtual and erect image, the magnification created by the mirror is
Question 39 :
How does the power of a lens change if its focal length is doubled?<br>
Question 42 :
In case of a real and inverted image, the magnification of a mirror is:
Question 43 :
If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be
Question 44 :
What is the size of image when position of object is at F, position of image is at infinity and image formed through concave mirror?<br>
Question 45 :
If the focal length of a lens is $50\;cm$, its power would be
Question 46 :
Choose the correct answer:<br>The nature of image formed by convex mirror is:
Question 48 :
A ray of light travelling in air strikes the surface of glass at angle of $45^{\circ}$. The angle of refraction in the glass will be :
Question 49 :
Ray optics fail when the size of the obstacle is :
Question 50 :
Fill in the blanks:Principal axis is also called ________ of the lens.
Question 51 :
In case of refraction of light<br/>a) Frequency changes <br/>b) Speed changes <br/>c) Wavelength changes<br/>
Question 52 :
A sound wave is travelling in a medium in which the velocity is $v$. It is incident in the second medium in which the velocity of the wave is $2v$. What should be the minimum angle of incidence in the first medium, so that the wave fails to cross the surface of separation of the two media?
Question 53 :
Light of wavelength$\displaystyle 6600\overset { \circ }{ A }$ travelling in air gets refracted in water. If the speed of light in air is$\displaystyle 3\times { 10 }^{ 8 }{ m }/{ s }$ and R.I of water is 4/3. Find frequency of light in air.
Question 54 :
An object is placed at a distance of $f/2$ from a convex lens. The image will be
Question 55 :
In the displacement method, a convex lens is placed in between an object and a screen. If one of the magnification is $3$ and the displacement of the lens between the two positions is $24$cm, then the focal length of the lens is:
Question 57 :
A double concave thin lens made out of glass ($\mu = 1.5 $) have radii of curvature 500 cm. This lens is used to rectify the defect in vision of a person. The far point of the person will be at
Question 58 :
The relation among u, v and f for a mirror is
Question 59 :
What is the type of a lens of $Power = -4D$ ?
Question 60 :
An object is kept at 15 cm from a convex mirror of focal length 25 cm. What is the magnification?<br/>
Question 62 :
When an object is placed on the principal axis of a convex lens at two different positions, it produces the images with magnification +2 and -4 respectively. How many times more away from the lens the image will be formed in the second position as compared to the first position?<br>
Question 63 :
Two thin lenses of focal lengths $20 cm$ and $25 cm$ are placed in contact. The effective power of the combination is
Question 65 :
Images formed by which of the following arrangement isnot Virtual and erect ?
Question 66 :
Refraction index of water is 4/3. Calculate speed of light in water.
Question 67 :
A light ray travels from optically denser medium to optically rarer medium, if the angle of incidence and refraction at point of incidence are $\angle i$ and $\angle r$ respectively, then find the angle of deviation in terms of $\angle i$ and $\angle r$.
Question 68 :
A man can see distinctly from a distance of $0.5$ metre. If he wants to read a book placed at a distance of $25 \,cm$, then what should be the power of lens ?
Question 69 :
Two thin lenses, when in contact, produce a combination of power$+10D$. When they are $0.25m$ apart, the power reduces to $+6D$. The focal lengths of the lenses (in m) are
Question 70 :
Focal length of a convex lens is 10 cm. When the object is moved from 15 cm to 25 cm, the magnitude of linear magnification
Question 71 :
Image of an object at infinity is formed by a convex lens of focal length $30 \ cm$ such that the size of the image is $2 \ cm$. If a concave lens of focal length $20\  cm$ is placed in between the convex lens and the image, at a distance $26\  cm$ from the convex lens, size of the new image is:
Question 72 :
The reflecting surface is given by $y = \dfrac{10L}{\pi} \sin \dfrac{\pi x}{5L}$. The co-ordinates of the point where a horizontal ray becomes vertical after reflection is:
Question 73 :
A ray of light going towards the centre of curvature of a convex mirror ............
Question 74 :
A short linear object of length $b$ lies along the axis of a concave mirror of focal length $f$ at a distance $u$ from the pole of the mirror. The size of the image is approximately equal to:<br/>
Question 75 :
An object is placed at $30$ cm distance from a concave mirror of focal length $20$ cm, then nature, magnification of the image will be:
Question 76 :
A spherical convex surface separates object and image space of refractive index $1$ and $4/3$ respectively. If radius of curvature of the surface s $0.1\ m$, its power is
Question 77 :
A short linear object of length $b$ lies along the axis of a concave mirror of focal length $f$ at a distance u from the pole of the mirror. The size of the image is approximately equal to :<br>
Question 78 :
Aconvex lens of radii of curvature 20 cm and 30 cm respectively. It is silveredat the surface which has smaller radius of curvature. Then it will behave as $(\mu_g\, = \, 1.5)$
Question 80 :
Three convex lenses are available having focal lengths of $4 cm, 40 cm$ and $4 m$ respectively. Which one could be used as magnifying glass?