Choose the correct answer

1.(c) 7

2.(d) 900

3.(b) two

4.(c) 0.0007

5.(d)0.0004

Explanation:

(1) White light after reflection through prism splits into 7 colors.

(2) Arabs and Chinese knew about lenses in about 900 AD

(3) There are Two more colors in the spectrum which cannot be seen with naked eye.

(4) Wavelength of red light is 0.0007mm

(5) Wavelength of violet light is 0.0004mm

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

b. a lightning bug, plug of grass, and a worm