Question 3 :
The least distance of distinct vision for a defective eye is $75$ cm. What should be the focal length of the lens which will be used to read a book clearly at $25$ cm?
Question 9 :
CV Raman got the Nobel Prize for his experiment on :
Question 11 :
What is the time difference between actual sunset and apparent sunset?
Question 13 :
The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light:<br/>
Question 14 :
For the angle of minimum deviation of a prism to be equal to its refracting angle, the prism must be made of a material whose refractive index lies between:
Question 15 :
At which place in eye,image is formed of a person is far-sightedness (hypermetropia) ?
Question 18 :
The sun appears red at the time of sun-rise and sun-set. This is because:
Question 20 :
In context of scatteringFine particles : ____ wavelength : : large particles : _____ wavelength
Question 21 :
Fill in the blank spaces by choosing the correct word.A prism is a piece of transparent material having three rectangular surfaces and .......... triangular surfaces.
Question 24 :
The spectrum, in which the colours are separated using a narrow source of light, is called:
Question 25 :
A defect, in which a person suffering from is unable to see in all directions equally well, is:
Question 26 :
The power of two convex lenses $A$ and $B$ are $8$ diopters and $4$ diopters respectively. If they are to be used as a simple microscope, the magnification of
Question 27 :
If an object is placed $10\ cm$ infront of a concave mirror of focal length $20\ cm,$ the image will be
Question 28 :
If an object is placed at '$C$' of a concave mirror, the position of the image is ______
Question 29 :
Various optical instruments like telescopes, microscopes, camera uses which property of light?<br>
Question 30 :
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 31 :
To construct a ray diagram, you need a minimum of  _______ ray(s) whose path(s) after refraction through the lens are known.
Question 32 :
A person uses spectacles of power $+2\ D$. He is suffering from
Question 33 :
A unit vector along the incident ray of light is $\hat{i}$. The unit vector for the corresponding refracted ray of light is $\hat{r}\cdot \hat{n}$, a unit vector normal to the boundary of the medium and directed towards the incident medium. If $\mu$ is the refractive index of the medium, then Snell's law (second law) of refraction is :
Question 34 :
A convex mirror used for rear view on an automobile has a radius of curvature of 3.00m. If a bus is located at 5.00m from this mirror, find magnification?<br>
Question 35 :
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 37 :
Under which of the following conditions will a convex mirror of focal length <i>f</i> produces an image ofreal object that is erect, diminished and virtual
Question 38 :
Lens A produces a magnification of -0.8 whereas lens B produces a magnification of +0.8. Which one of the following applies to lenses A and B?
Question 39 :
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 40 :
$ \dfrac{\sin i}{\sin r}  =$constant, the value of constant depends upon<br/>a) Pair of media <br/>b) Color of incident light<br/>c) Wave length <br/>d) Refracting nature of material<br/>
Question 41 :
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 42 :
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 43 :
A plane glass plate is placed over a various coloured letters (violet, green, yellow, red). The letter which appears to raised more
Question 46 :
A beam of light passing from air enters into the glass. Identify which of the following statements is true?<br/>
Question 47 :
The mirror used in automobiles to see the rear field of view is
Question 49 :
The power of a lens having a focal length of $1\;cm$ is :
Question 50 :
The heat of sun focussed by a convex lens on a piece of paper is capable of
