Give reason for the following: a) Metals are regarded as electropositive elements. b) When a piece of copper metal is added to a solution of Zinc sulphate, no change take place, but the blue colour of copper sulphate fades away when a piece of zinc is placed in its solution . c) Articles of aluminium do not corrode even though alluminium is an active metal.

What type of questions asked from the lesson of magnetic effect of electric current 

Wavelength of green light is

A) 400-450 nm

B) 500-550 nm

C) 660-720 nm

D) 720-800 nm

What is the difference between anaerobic & aerobic respiration? Name some organism that uses the aerobic mode of respiration?

What are the main components of our environment? Explain each of them briefly.

What are examples of hydrotropism plants?