DIFFERENCES FROM PAST PAPERS (2010)

1. Hydrometer & Hygrometer

Hydrometer
Hydrometer is an instrument used to measure the specific gravity of liquids. It should be noted that specific gravity is the ration of the density of the liquids to density of water.

Hygrometer:
A hygrometer is an instrument used to measure relative humidity. A simple form of hygrometer consists of two thermometers, one of which has a dry bulb and the other, a wet bulb.

2. Perimeter & Telemeter

Perimeter:
A perimeter is a path that surrounds an area. The word comes from the Greek peri (around) and meter (measure). The term may be used either for the path or its length - it can be thought of as the length of the outline of a shape. The perimeter of a circular area is called circumference.

Telemeter:
A telemeter is a device used to remotely measure a quantity. Telemeters are generally the physical devices used in telemetry. Electronic devices are widely used in telemetry and can be wireless or hard-wired, analogue or digital. Other technologies are possible, however, such as mechanical, hydraulic and optical.

3. Isotope & Isomer

Isotope:
Isotopes are different types of atoms of same element whose atoms of same element whose atomic number is same but atomic mass is different. Isotopes have similar chemical properties but different physical properties.

Isomers:
Isomers are compounds with the same molecular formula but different structural formula. Isomers do not necessarily share similar properties unless they have same functional groups.

OR

Isotopes and Isomers
An isotope refers strictly to pure elements. Atoms of the same element that have different numbers of neutrons in their nuclei are called isotopes. For instance, hydrogen-1 (1H) and hydrogen-2 (2H or deuterium) are isotopes of each other.

An isomer refers strictly to molecules. Two molecules that have the same composition (i.e., the same molecular formula) but are different in the connectivity, shape or orientation, are called isomers. For instance, n-propanol (1-propanol) and isopropanol (2-propanol or rubbing alcohol) are isomers of each other. Ethanol is not an isomer of propanol, however, because they have different formulas.

4. Flying Mammal & Bird

Flying Mammals:

i. Mammals are the class of animals which give birth to live offspring and feed their young ones on milk from their breast.

ii.Flying mamma is the type of animal which belongs to mammalian group with additional quality of flying.

iii.Bats are representative animals of this group.

iii.Bats have many unusual characteristics.

v.They cannot walk very well because of skin that reaches over its front and back legs.

vi. It flies at night and stays in caves and other dark places during the day.

vii.Hanging upside down by the claws of its back legs, it looks like flying mice.

Birds:
i. Birds are winged, bipedal, endothermic warm-blooded, egg laying vertebrate animals.

ii.There are around 10,000 living species across the world.

iii.All birds have fore-limbs modified as wings and most can fly with few exceptions like ratites, penguins and number of various island species.

OR

Difference between Bats and Birds

The variation between bats and birds is their structure and class. Bats came from the Chiroptera and Aves family. Bats are webbed structured flying animals while birds are feathered winged animals. Bats are mammals, so they don’t lay eggs, compared to birds that are known as egg-laying animals. When flying, bats don’t flap their forelimbs completely compared to birds. Generally, bats have teeth which help them when eating while birds have beaks in picking up food and eating them. Bats are nocturnal animals; they hunt and go around their business at night and sleep during the day while birds work and hunt for food during daytime and sleep at night.

5. Vertebrates & Invertebrates (see 2005)