Pollution of Air and Water — Science STD 8 — Question

Describe with the help of a diagram, an instrument which can be used to detect a charged body.

Electric heating devices (like an electric heater or a stove) are often considered more convenient than traditional heating methods (like burning firewood or charcoal). Give reasons to support this statement, considering societal impact.

Moon does not have light of its own. How are we able to see the Moon?

Look at this food chain:
Grass → Grasshopper → Frog → Snake
If frogs disappear from this ecosystem, what will happen to the population of grasshoppers and snakes? Why?

Given below are certain food items required for proper nourishment of adolescents. Name the nutrients present in the food items and write their functions.

Food items	Major nutrients	Functions
Pulses and nuts
Oranges and amla
Sugar and roti
Oils
Vegetables

What are the products obtained on fraction distillation of coal tar?

State some of the characteristics of chemical changes brought about by the chemical effect of electric current.

What is the difference between a meteor and a meteorite?

Briefly mention, which of the following will cause regular reflection of light and which diffuse reflection of light. Polished wooden table.

Different between ‘endangered species’ and extinct species.