DIFFERENCES FROM PAST PAPERS (2004)

1. Periscope & Pyrometer:

Periscope:
Instrument used by submarines to see above the surface of the sea.

Pyrometer:
Instrument used for measuring high temperatures.

2. Cell & Battery

Cell:
A cell is a DC voltage source in which chemical energy is converted into electricity.

Battery:
It is a device which produces electricity through the use of acid and other chemicals. It is assembly of many cells.

3. Perimeter & Altimeter

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.

Altimeter:
An altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.

4. Pelage & Plumage

Pelage:
It is a growth of hair/fur/wool covering the skin of animals.

Plumage:
Plumages are feathers covering the body of birds.

5. Smog & Smoke

Smog
Smog is formed by the interaction of pollutants present in the air in presence of sun light (photochemical smog), it usually restricts visibility and is hazardous to health.

Smoke:
Smoke is the thin fine particles usually result from the combustion.