Write the name and formula of the 2nd member of homologous series having general formula C_nH_2n+2

Name the type of asexual reproduction in which two individuals are formed from a single parent and the parental identity is lost. Draw the initial and the final stages of this type of reproduction. State the event with which this reproduction starts.

To find the image-distance 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 move the screen to focus the object?

(b) What happens to the size of image-does it increase or decrease?

(c) What happen when he moves the object very close to the lens?

What is the magnification of the images formed by plane mirrors and why?

What is meant by power of a lens?