Observe the following chemical reactions i) Fe_2O_3 + 2Al to 2Fe + Al_2O_3 ii) ZnO + C to Zn + CO iii) Fe_2O_3 + 3C to 2Fe + CO iv) Al_2O_3 + 3C to 2Al + 3CO Which of the above reaction is wrong? How is the metal present in the wrong equation extracted? Which of the above reaction can be used to join the broken parts of the machines. Why?

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?