Education

CBSE-Light Increase the magnification and sharpness of the image in optical instruments Many optical instruments consist of a number of lenses. They are combined to increase the magnification and sharpness of the image. The net power (P) of the lenses placed in contact is given by the algebraic sum of the individual powers P1, P2, P3,... as P = P1+P2+P3.

 CBSE notes-Light What is the nature, size and position of the image formed of an object at infinity? Explain how it is used as a doctor’s mirror. When an object is placed at infinity from a concave mirror, the image formed is (i) real and inverted (ii) highly diminished and (iii) at the focus When the object is at infinity, the image is formed at the focus of the concave mirror, hence the mirror can concentrate all the parallel rays of the light to its focus. This explains the use of concave mirror as a doctor’s head-mirror. A concave mirror is used as a head-mirror by the doctors to concentrate light on the body parts to be examined.

CBSE notes-Light   Distinguish between a real image and a virtual image? The image which can be observed through naked eye is called real image and the image which cannot observed through naked eye is called virtual image.

CBSE notes-Light What is the nature, size and position of the image formed of an object at infinity? Explain how it is used as a doctor’s mirror. Solution:When an object is placed at infinity from a concave mirror, the image formed is (i) real and inverted   (ii) highly diminished and   (iii) at the focus When the object is at infinity, the image is formed at the focus of the concave mirror, hence the mirror can concentrate all the parallel rays of the light to its focus. This explains the use of concave mirror as a doctor’s head-mirror. A concave mirror is used as a head-mirror by the doctors to concentrate light on the body parts to be examined.  

CBSE notes-Light What is lateral inversion? Solution:If an object is placed in front of a plane mirror, then the right side of the object appears to be on the left side of the image and the left side of the object appears to be on the right side of its image. This change of sides of an object and its mirror image is called lateral inversion.