Friction — Science STD 8 — Question

What is acne?

In which zone of a candle flame: Partial combustion of fuel takes place.

Why are measuring cylinders always designed narrow and tall instead of wider and shorter like a beaker?

A gas is utilised by the trees and plants in photosynthesis. The same gas also traps the heat rays reflected by the Earth and is also given out by humans during respiration. Name the gas and the phenomenon of increase in temperature for which it is responsible.

Name the petroleum product commonly used for electric generators.

What causes the red colour in tomatoes?

In the following statements, the underlined words are jumbled up. Write them in their correct form. Carbon dioxide, thaneme, nitrous oxide and water vapour are known as heengrouse sesga.

Name any two human diseases caused by protozoa.

Fill in the blanks with suitable words. Time taken by an object to complete one oscillation is called _________.