Question 3 :
To construct a ray diagram, you need a minimum of  _______ ray(s) whose path(s) after refraction through the lens are known.
Question 4 :
If an object is placed at '$C$' of a concave mirror, the position of the image is ______
Question 5 :
Which of the following is not a characteristic of image formed by Concave lens ?
Question 7 :
The focal length of a combination of lenses formed with lenses having powers of $+2.50\ D$ and $-3.75\ D$ will be
Question 9 :
State the direction of incident ray which after reflection from a spherical mirror retraces its path:
Question 12 :
If the light moving in a straight line bends by a small but fixed angle, it may be a case of<br>$(i)$reflection<br>$(ii)$refraction<br>$(iii)$diffraction<br>$(iv)$dispersion<br>
Question 13 :
Magnification is 0.5 when the object distance is 10 cm. Find the power of the concave lens :
Question 14 :
The power of a lens having a focal length of $1\;cm$ is :
Question 15 :
What type of mirror can be used alone to obtain a real image of a real object?
Question 16 :
A spherical mirror and a thin spherical lens have each a focal length of $-15$ cm. The mirror and lens are likely to be :<br/>
Question 17 :
The ratio of the sine of angle  of incidence to the sine of angle of refraction is a constant for :
Question 18 :
The focal length of a convex lens is $5\,cm$,where should the object be placed to get  a real image with same size as that of object:
Question 19 :
A ray of light travels from air to glass at an angle of incidence of $37^{\circ}$, the angle of refraction is $24^{\circ}$. What is the refractive index of glass?<br/>(Given: $\sin 37^{\circ} = 0.60, \sin 24^{\circ} = 0.40)$
Question 20 :
<br>Which is the human organ which behaves like an optical instrument having lens and a screen?
Question 22 :
The power of a lens being $+4$ dioptres suggests that it is a
Question 23 :
Fill in the blanks:Principal axis is also called ________ of the lens.
Question 24 :
The angle of incidence for a ray of light passing through the centre of curvature of a concave mirror is :
Question 25 :
In case of a virtual and erect image, the magnification created by the mirror is
Question 27 :
A virtual image larger than the object can be produced by a
Question 29 :
The radii of curvature of both the sides of a convex lens are $15cm$ and if the refractive index of material of the lens is $1.5$. Then focal length of lens in air is _______cm.
Question 31 :
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 32 :
A ray passing with which part of a lens emerges undeviated ?
Question 33 :
A ray of light passing through the .......... of the lens, passes on undeviated.
Question 34 :
"Value of refractive index remains same for light rays with different wavelength and for a particular material"
Question 35 :
During refraction through a glass block, the angle of refraction _______.
Question 36 :
A light ray travels at some angle (not head on) from water in a rectangular aquarium, through the glass side, and out into air . The indices if refraction for water, glass, and air are 1.33, about 1.6, and 1.0, respectively.<br/>Rank the material;s according to the angles of refraction  made by the light ray with the normal in each, greatest first.
Question 37 :
An object 20 cm from lens, has a virtual image at 10 cm from the object. The power of the lens is
Question 38 :
In passing through a boundary, refraction will not take place if
Question 39 :
The maximum magnification that can be obtained with a convex lens of focal length $2.5\ cm$ is ( the least distance of distinct vision is $25\ cm$)
Question 40 :
The image formed by the given convex mirror when it is inside focal distance is:
Question 41 :
Height of the image of an object on an principal axis produced by a convex lens is double the focal length of lens is $20 cm$, then image distance from the lens is:
Question 45 :
Ratio of the size of the image to the size of the object is known as:
Question 46 :
A ray of light is incident on the surface of transparent medium at an angle of $45^o$ and is refracted in the medium at an angle of $30^o$. What will be the velocity of light in the transparent medium ? <br/>
Question 47 :
If a $3cm$ tall object placed perpendicular to principal axis of a convex lens of focal length $15cm$ produces a real invented image of height $15cm$, then its object distance $(u)$ is ................ and image distance $(v)$ is ................
Question 48 :
A convex mirror of focal length $f$ forms an image which is $\dfrac{1}{n}$ times the object. The distance of the object from the mirror is:
Question 50 :
An object of height $1.5\ cm$ is placed on the axis of a convex lens of focal length $25\ cm$. A real image is formed at a distance of $75\ cm$ from the lens. The size of the image will be
