Question

A. VERY SHORT ANSWER TYPE QUESTIONS 1. Name the main constituents of the air. 2. Which component of air is used by plants to make their food ? 3. When is winnowing more effective? 4. What is the relative proportion of nitrogen and oxygen in the air ? 5. Name a device which uses wind energy to generate electricity.​

Answer 1

Answer:

Let x be the one angle.

So, the complement of x=90

o

−x.

Given, two complementary angles differ by 20

o

.

⇒ x+(x−10

o

)=90

o

⇒ 2x−10

o

=90

o

⇒ 2x=100

o

⇒ x=50

o

.

Then, the angles are x=50

o

and other angle is x−10

o

=50

o

−10

o

=40

o

Answer 2

$\large\bold\orange{\underline{Answer:-}}$

1. Main constituents of air are :-

• Nitrogen (78%)
• Oxygen (21%)
• Tiny amounts of carbon dioxide, water vapour, ozone (1%)

2. Component of air used by plants to make their own food is $\bold{Carbon \ Dioxide}$

3. Winnowing is most effective when there is a blowing of wind otherwise some of the lighter particles may get mixed with the grains.

4. Nitrogen = 78% and Oxygen = 21%

5. $\bold{Windmill}$ is the device which uses wind energy to generate electricity...