An object 4cm in size is placed 25cm in front of a concave mirror of focal length 15cm. At what distance from the mirror should the screen be kept so that a sharp image of the object can be obtained on screen? Find the nature and height of the image.

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?

Why is water liquid at room temperature?