Calculate the values of the following : 

1. The total resistance of the circuit
2. The total current
...

Draw ray diagrams to show the nature, position and relative size of the image formed by a convex...

Explain in brief how stability of DNA content of a species is ensured in sexually reproducing...

What are chromosomes?

Plants have neither a nervous system nor muscles, even then they respond to stimuli. For example, the...

Write a test to identify the gas evolved (if any) during the reaction of these metals with water.

Name two metals which react violently with cold water. List any three observations which a student...

 With the help of an activity, explain the conditions under which iron articles get rusted. 

Why can metals high up in the reactivity series not be obtained by reduction of their oxides by...

 ‘‘Displacement reactions also play a key role in extracting metals in the middle of the reactivity...

 ‘‘Excessive use of chemicals and pesticides in agriculture adversely effect the environment.’’...

Define electric power. When do we say that the power consumed in an electric circuit is 1 watt ?

 A wire of resistance R is cut into three equal parts. If these three parts are then joined in...

 An object is placed at a distance of 60 cm from a concave lens of focal length 30 cm. Use lens...

State the role of phloem in the transport of materials in plants.

The transport system in plants is relatively slower than in animals. Give reasons.

Besides minimising the loss of blood, why is it essential to plug any leak in a blood vessel ?...

 Draw labelled diagrams to show different stages of budding in Hydra.