III. ANSWER BRIEFLY/write any 6 only):
39. Explain how friction can be minimised.
40. Give any two applications of a concave and convex mirror.
41. Explain the working of thermos flask.
42. What is electroplating? Explain how it is done.
13. Why does the fish die when it is taken out of water?
4. How can we prove that the electrons carry negative charge?
.Write the economic importance of gymnosperm.
How are we preparing pickles? What are the steps involved in
What are the functions of skeleton in human body?
Answers
Answer:
economic importance of gymnosperm is the answer
Answer:
39) By polishing the surface, as polishing makes the surface smooth and friction can be reduced. Using lubricants such as oil or grease can reduce the friction between the surfaces.
40) a) One of the most common uses for the convex mirror is the passenger-side mirror on your car. b) used for rear view mirror.
b) One of the most common uses for the concave mirror is headlights and shaving mirrors are used for shaving.
42) Electroplating is the coating of metal on any material using electricity. Electroplating involves passing an electric current through a solution called an electrolyte. When the electricity flows through the circuit they make, the electrolyte splits up and some of the metal atoms it contains are deposited in a thin layer on top of one of the electrodes—it becomes electroplated.
43) Fish dies because fish respire with the help of gills and we all know this very well. It is the structure of gills that helps fish respire inside water. It cannot breathe through the atmospheric oxygen and hence the fishes die when taken out of the water.
47) The skeletal system works as a support structure for your body. It gives the body its shape, allows movement, makes blood cells, provides protection for organs and stores minerals. The skeletal system is also called the musculoskeletal system.
46)Pickles can be prepared using one of two main methods: lactic acid fermentation of vegetables, either with or without the addition of salt the preservation of vegetables in acetic acid . The products made by these two methods are very different -each one has its own distinctive taste and texture.
If helped than please mark it as Brainliest answer.