Optical images. Real Image vs Virtual image. Difference between Real and Virtual Images.

Class 10 Physics. Physical Science. Optics. Light. Science.

Today, we are going to learn about two types of images, the real images and the virtual images.

After watching this video, you will be able to answer all these questions yourself.



Let start.

What is an image?

Before answering this question, we will take a look at some of the optical devices, through or against which the rays of light interact.

Here, we will show you the optical paths of rays about the devices , through 3d animations.

First, let us have a plane mirror.

Let P be the point on the top of this yellow arrow object. From the point P, rays of light are spreading all around. Some of the rays will be directed towards the plane. And will come back again after reflection. Here different colored particles are used to indicate the incident rays and the reflected rays separately.

After reflection, the rays diverge further. Looking back of it, you can imagine that the reflected rays are perhaps emitting from a point behind the mirror. It is as if the lights are coming out from the point of P dash. In this case, an image of the point P will be formed at point P dash. Underneath the p-dashed point, an image, identical to the entire arrow is formed.

Next, we will see the path of the rays about a convex mirror.

Here, too, an arrow-like object is placed in front of the mirror. The top point of the arrow is P. The rays of light from the point P will be reflected back by the mirror. The reflected rays appear to be coming out of a Point P dash, at the back of the mirror. Therefore, the image of the point P will be formed at the point P Dash. Underneath the p-dashed point, a smaller right side up image of the entire arrow is formed.

Concave lens.

Here the rays emitted from the point P will be passing through it. After the refraction, the rays tend to spread. If you look closely, you can imagine that the refracted rays are perhaps coming out of some other point in front of the lens. An image of the point P is formed at that P dash point. Underneath the p-dash point, a right side up image of the entire arrow is formed.

Now, we will see the image formation in a convex lens.

Here, too, the rays are refracted through. However, the refracted rays do not spread. Instead, they all converge into a point. At that point, an image of the point P will be formed. The image is P dash. Above the point P dash, an image of the entire arrow is generated. This image is inverted with respect to the object.

And now, check out this image formation, by a concave mirror.

Here the rays of light, emitted from the point P, is reflected back, by the concave mirror. The reflected rays do not diverge here. But converge into a Point, at the p dash point . At that point an image of the point P will be formed. The image is P Dash. An inverted image of the entire arrow is formed above the point P dash is in place.

So, we realized all types of image formation, in 3d animation.

Now,

What is a Real Image?

In situation 4 and 5, we see that the rays of light are meeting together, or converging at one point after reflection or refraction. The images, formed in these procedures are called Real Images.

That is, the definition of real image is like this

If the rays of light, emitted from a Point source, undergo a reflection or refraction, and after reflection or refraction, converge into a second point, then the second point is termed as the real image of the point source.


What is a virtual image?

In the previous situation of number 1, number 2 and number 3, we saw that the rays are not converging. But diverging, instead. If you inspect the trajectories of the reflected or refracted rays, you may find a second point, from which the reflected or refracted rays appear to be coming out from. This second point is the virtual Image of the first one. Do remember, It is an imaginary point.



Therefore, the definition of Virtual Image is


If the rays of light, emitted from a Point source, undergo a reflection or refraction, and after reflection or refraction, diverge around, then the point divergence is called the virtual image of the point source.


So, we understand, the two types of images. Real image and virtual image.

Now let's come back to our first ever question. What is an image?

You can brilliantly define it now, like this


If the rays of light, emitted from a Point source, undergo a reflection or refraction, and after reflection or refraction, if they converge into a point or appear to diverge from a point, then the point of convergence or the point of divergence is termed as the image of the point source.


Reflection and refraction of light.

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