Question 1 :
The focal length of a combination of lenses formed with lenses having powers of $+2.50\ D$ and $-3.75\ D$ will be
Question 2 :
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 3 :
Object when placed at ________ in front of concave mirror magnification of -1 is obtained.
Question 5 :
The heat of sun focussed by a convex lens on a piece of paper is capable of
Question 7 :
Assertion: Magnetic field lines are continuous and closed.
Reason: Magnification of a convex mirror is always positive, but that of a concave mirror may be both positive or negative.
Question 8 :
The focal length of a lens can be expressed in :
Question 9 :
A beam of light passing from air enters into the glass. Identify which of the following statements is true?<br/>
Question 13 :
The ratio of the sine of angle  of incidence to the sine of angle of refraction is a constant for :
Question 14 :
A person uses spectacles of power $+2\ D$. He is suffering from
Question 15 :
If an object is placed $10\ cm$ infront of a concave mirror of focal length $20\ cm,$ the image will be
Question 16 :
<br>Which is the human organ which behaves like an optical instrument having lens and a screen?
Question 17 :
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 18 :
State the direction of incident ray which after reflection from a spherical mirror retraces its path:
Question 19 :
A plane glass plate is placed over a various coloured letters (violet, green, yellow, red). The letter which appears to raised more
Question 20 :
State whether true or false:A concave lens forms a magnified or diminished image depending on the distance of object from it.<br/>
Question 21 :
Which of the following are common to images formed by both Concave and Convex lens ?
Question 22 :
Two thin lenses of focal lengths $f_{1} and f_{2}$ are in contact and coaxial. The power of the combination is :<br/>
Question 23 :
Identify the phenomenon due to which a converging lens forms an image :
Question 25 :
A converging lens has a focal length of $50 cm$. The power of the lens is
Question 29 :
What type of mirror can be used alone to obtain a real image of a real object?
Question 30 :
The power of a lens having a focal length of $1\;cm$ is :
Question 31 :
What is the angle of incidence when a ray of light incident on a concave mirror from its centre of curvature?
Question 32 :
What is the formula for spherical mirrors for object distance p and image distance q ?<br/>
Question 33 :
Find the power (with sign) of a concave lens of focal length $20cm$.<br/>
Question 35 :
The incident ray, the normal at the point of incidence and the refracted ray:
Question 37 :
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 38 :
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 39 :
State whether true or false.<br/>The images formed by a convex mirror are always erect and enlarged.
Question 41 :
The distance between an object and its real image produced by a converging lens is $0.72\ m$. The magnification is $2$. What will be the magnification when the object is moved by $0.04\ m$ towards the lens?
Question 42 :
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 43 :
The power of a lens is negative. State whether it is convex or concave?<br/>
Question 44 :
The relation between the linear magnification $m,$ the object distance $u$ and the focal length $f$ is
Question 45 :
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 46 :
A ray of light travelling in air is incident on the plane of a transparent medium. The angle of incident is $45^0$ and that of refraction is $30^0$. The refractive index of the medium with respect to air is:
Question 47 :
State whether the following statement is True or False. <br/>A real image can be obtained by putting an object at any distance from a convex mirror
Question 49 :
A ray of light coming parallel to the principal axis after passing through a convex lens, has passed through its :
Question 50 :
Fill in the blanks:Principal axis is also called ________ of the lens.
