Chemical Effects of Electric Current — Science STD 8 — Question

The use of aluminium has increased over copper for the manufacture of electrical cables.

Phosphorus is kept in water.

The soil should be ploughed.

Why does the increased level of nutrients in the water affect the survival of aquatic organisms ?

The sole of our shoes get worn out after a period of time.

Two persons are applying forces on two opposite sides of a moving cart. The cart still moves with the same speed in the same direction. What do you infer about the magnitudes and direction of the forces applied?

John and Radha were classmates since childhood. When Radha became eleven years old, she developed a little swelling on her neck. She visited the doctor who started medication for her. After a few years, John also developed a slight protrusion on his throat. He got worried and went to the doctor. But, the doctor assured him that it was a normal feature in boys while they are growing up. Can you think of any reasons for the difference in diagnoses?

The electrical charges generated by rubbing proper objects are static. They do not move by themselves.

Thyroid gland has special significance/importance in a frog.

What is the affect of introduction of an exotic species to an ecosystem?