The following figure illustrates binary fission in Amoeba in an incorrect sequence. 

• III, II, IV, I

• III,IV,II,I

• II,III,IV,I

• II,III,IV,I

If you are to determine the focal length of a convex lens, you should have

• A convex lens and a screen

• A convex lens and a lens holder

• A lens holder, a screen holder and a scale

• A lens holder, a screen holder and a scale

A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see,

• a very blurred image on the wall opposite to the mirror

• an erect and magnified image of the tree in the mirror

• no image as the screen has been removed

• no image as the screen has been removed

A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting best results he should focus,

• a distant tree or an electric pole

• a well-illuminated distant building

• well-lit grills of the nearest window

• well-lit grills of the nearest window

Write the name formula of the first member of the carbon compounds having functional group-CHO.

Write the name and formula of a molecule made up of three atoms of oxygen.

Why do all the elements of the (a)same group have similar properties, (b) same period have different properties.

18.

An element E has following electronic configuration.
K   L     M
2   8     6

a) To which period of the periodic table does element E belong?

b) To which group of the periodic table does element E belong?

c)State the number of valence electrons present in element E.

d) State the valency of the element E.

Name the oxidizing agent used for the conversion of ethanol to ethanoic acid. Distinguish between ethanol and ethanoic acid on the basis of (i) litmus test,(ii) reaction with sodium hydrogen carbonate.

Na, Mg and Al are the elements having one, two and three valence electrons respectively. Which of these element (i) Has the largest atomic radius (ii) is least reactive? Justify your answer stating the reason for each.