Differentiate between mirror and lens.
Important Questions on Light – Reflection and Refraction
A student wants to obtain magnified image of an object AB as on a screen. Which one of the following arrangements shows the correct position of AB for him/her to be successful?
If a lens can converge the sun rays at a point away from its optical centre, the power of this lens is _____.
A converging lens forms a three times magnified image of an object, which can be taken on a screen. If the focal length of the lens is , then the distance of the object from the lens is _____.
The following diagram shows the use of an optical device to perform an experiment of light.
As per the arrangement shown, the optical device is likely to be a _____.
An object is placed at a distance in front of a convex lens of focal length .
(i) Calculate the distance of the image from the lens.
(ii) Calculate the magnification of the image.
A virtual, diminished image is formed when an object is placed between the optical centre and the principal focus of a lens.
(i) Name the type of lens which forms the above image.
(ii) Draw a ray diagram to show the formation of the image with the above stated characteristics.
To find the image for varying object distances in case of a convex lens, a student obtains on a screen a sharp image of a bright object placed very far from the lens. After that he gradually moves the object towards the lens and each time focuses its image on the screen.
(a) In which direction-towards or away from the lens does he moves the screen to focus the object?
(b) What happens to the size of image-does it increase or decrease?
(c) What happens when he moves the object very close to the lens?
