PHYSICS [5 Mark Question Answer]

difference between real and virtual images.

Real images	Virtual images
it can be obtained on a screen	It can't be obtained on a screen
it is inverted (upside down with respect to the object)	It is erect with respect to the object
It is formed when two or more reflected rays intersect each other at a point in front of the mirror	It is formed when two or more reflected rays appear to intersect at a point behind the mirror

A light ray, parallel to the principal axis, coming from a point on object AB is reflected from the surface of the mirror, it passes through the principal focus and the other ray striking normally to the mirror reflects back and passes through the center of curvature. These two reflected rays, when produced backward, coincide at a point where the image is formed. The image, A'B' is virtual, erect, and magnified in size.

A light ray, parallel to the principal axis, coming from a point on object AB is reflected from the surface of the mirror, it passes through the principal focus and the other ray striking normally to the mirror reflects back and passes through the center of curvature. These two reflected rays, when produced backward, coincide at a point where the image is formed. The image, A'B' is virtual, erect, and magnified in size.

A light ray coming from a point on object AB passes through the principal focus and after reflection, it becomes parallel to the principal axis in accordance with laws of reflection and the other ray passing through the centre of curvature strikes the mirror normally i.e. 90 degrees. Hence it will reflect back. These two reflected rays coincide at a point where the image is formed. The image, A'B' is real, inverted, and diminished in size.

A light ray when produced backwards passes through principal focus as shown in the problem figure. We draw the normal through the centre of curvature at the point of incidence and draw the reflected ray at an angle equal to the angle of incidence thus following the laws of reflection. The reflected ray is parallel to the principal axis. The other ray is passing through the centre of curvature as shown in the problem figure. This ray retraces its incident path because it strikes the mirror normally i.e. 90 degrees. These two reflected rays when produced backwards coincide at a point where the image is formed. The image, A'B' is virtual, erect, and diminished in size.

A light ray coming from a point on object AB is reflected from the surface of the mirror, it passes through the principal focus and the other ray passing through the center of curvature strikes the mirror normally i.e. 90 degrees. Hence it will reflect back. These two reflected rays coincide at a point where the image is formed. The image, A'B' is real, inverted, and diminished in size.

A light ray when produced backwards passes through principal focus as shown in the problem figure. We draw the normal through the centre of curvature at the point of incidence and draw the reflected ray at an angle equal to the angle of incidence thus following the laws of reflection. The reflected ray is parallel to the principal axis. The other ray is reflected at the pole by an angle in accordance with the laws of reflection. These two reflected rays when produced backwards coincide at a point where the image is formed. The image, A'B' is virtual, erect, and diminished in size

A light ray coming from a point on object AB is reflected from the surface of the mirror. When this ray is produced backwards, it passes through the principal focus and the ray which traces its incident path after reflection, when produced backwards, passes through the centre of curvature. These two reflected rays coincide at a point where the image is formed. The image, A'B' is virtual, erect, and diminished in size The focal length was found to be 24 mm.

i = < r In accordance with the laws of reflection. As the incident ray AB is parallel to the principal axis PC, so the reflected ray Bf passes through the principal focus, F. in figure (i) < ABC = < CBF
But < ABC = alternate< BCF
Therefore< CBF = < BCF
And the ΔFBC is isosceles
BF = FC ... (i) Since the aperture is assumed to be very small, so the point of incidence B is close to P And BF = PF (approx.) ... (ii ) From (i) and (ii )
PF = FC Adding PF to both sides
PF + PF= PF + FC 2PF = PC
Now since PF = f, the focal length of the mirror
And PC = R, the radius of curvature of the mirror Therefore 2f = R
From here we can determine the focal length of the concave mirror i.e. half of radius of curvature  

Difference between convergent and a divergent beam of light.

Convergent beam	Divergent beam
1. Rays of light converge to a point as the beam progresses	Rays of light diverge from each other as the beam progresses
2. The rays concentrate at a point	The rays emerging from a point source
3. A parallel beam of light converges on passing through a convex lens	A parallel beam of light diverges on passing through a concave lens

The reflection takes place at the surface of the plane mirror in accordance with the laws of reflection in which the angle of incidence is equal to the angle of reflection.
The light coming from the letter p is reflected from the surface of the plane mirror. When these reflected rays are produced backward, they form an inverted virtual image of letter p which is the same in size of letter p.

Difference between a ray of light and a beam of light.

Rav of light	Beam of light
1. Ray of light is the path along which the light travels	Many rays of light form a beam of light
2. A ray of light can be emitted from any source in any direction	A beam of light can be emitted from a Laser source
3. A ray of light contains only one photon	A beam of light contains multiple photons

(i) Centre of curvature can be determined by constructing the imaginary sphere to which lens belongs.
(ii) Value of radius of curvature can be found by measuring the radius of this imaginary sphere geometrically.
(iii) The focal length is the midpoint of the pole and centre of curvature.
(iv) focal length of mirror = centre of curvature/2.

Centre of curvature = 2 .8 cm.
Focal length of mirror = 1.4 cm.
Focal length = radius of curvature/2.

difference between real and virtual images.

Real images	Virtual images
it can be obtained on a screen	It can't be obtained on a screen
it is inverted (upside down with respect to the object)	It is erect with respect to the object
It is formed when two or more reflected rays intersect each other at a point in front of the mirror	It is formed when two or more reflected rays appear to intersect at a point behind the mirror

Mirror formula is the relation between the focal length f of the mirror, the distance u of the object from the pole of the mirror, and the distance v of the image from the pole.
Mirror formula is
1/v +1/u = 1/f.
Size of body = 1.5 m.
Magnification of body = 1.5.
Magnification = height of image / height of object.
Height of image = magnification x height of object.
Height of image = 1.5 x 1.5= 2.25 m.