Why do cockroaches come out their places when lights are put out ?

Why do you call cockroach is a pest ?

Why do fishes die when taken out of water ?

How do cockroaches differntiate light and dark?

Why does on element emit light, when it is heated ?

Carry out the following osmosis experiment: Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now, Keep cup A empty. Put one teaspoon sugar in cup B. Put one teaspoon salt in cup C. Put one teaspoon sugar in the boiled potato cup D. Keep these for two hours. Then observe the four potato cups and answer the following: Explain why water does not gather in the hollowed out portions of A and D.

Every metal has a definite work function . Why do all photoelectrons not come out with the same energy if incident radiation is monochromatic ? Why is there an energy distribution of photoelectrons ?

Why do you think the noble gases are placed in a separate group ?

Answer the questions : When a tiny circular obstacle is placed in the path of light from a distant soureR, a bright spot is seen at the centre of the shadow of the obstacle, Explain why ?

How can we put off the fire if it breaks out?

What factors do you keep in mind to put out fire when it is spreading ?