List of practice Questions

Answer in brief. 

1. Why should we conserve biodiversity? 
2. Protected forests are also not completely safe for wild animals. Why? 
3. Some tribals depend on the jungle. How? 
4. What are the causes and consequences of deforestation? 
5. What is Red Data Book? 
6. What do you understand by the term migration?

The circumference of a circle is 31.4 cm. Find the radius and the area of the circle? (Take \(\pi\) = 3.14)

A circular flower bed is surrounded by a path 4 m wide. The diameter of the flower bed is 66 m. What is the area of this path? (\(\pi\) = 3.14)

Rashmi has a road map with a scale of 1 cm representing 18 km. She drives on a road for 72 km. What would be her distance covered in the map?

A circular flower garden has an area of 314 \(m^2\) . A sprinkler at the centre of the garden can cover an area that has a radius of 12 \(m\). Will the sprinkler water the entire garden? (Take \(\pi\) = 3.14)

Find the circumference of the inner and the outer circles, shown in the adjoining figure? (Take \(\pi\) = 3.14)

How many times a wheel of radius 28 cm must rotate to go 352 m? (Take \(\pi\) = \(\frac{22}{7}\))

Draw a labelled sketch of the human eye.

The minute hand of a circular clock is 15 cm long. How far does the tip of the minute hand move in 1 hour. (Take \(\pi\) = 3.14)

Find the area of the following circles, given that: 

1.  radius = 14 mm (Take \(\pi\) = \(\frac{22}{7}\) ) 
2.  diameter = 49 m 
3.  radius = 5 cm

Find the circumference of the circles with the following radius: (Take \(\pi\) = \(\frac{22}{7}\) ) 

1.  14 cm 
2.  28 mm 
3.  21 cm

What will happen if. 

1. we go on cutting trees. 
2. the habitat of an animal is disturbed.
3. the top layer of soil is exposed

In a model of a ship, the mast is 9 cm high, while the mast of the actual ship is 12 m high. If the length of the ship is 28 m, how long is the model ship?

Choose the correct option.
Image formed by a plane mirror is

Choose the correct option.
Angle of incidence is equal to the angle of reflection.

Fill in the blanks in the following.
1. A person 1 m in front of a plane mirror seems to be ___ m away from his image.
2. If you touch your ___ ear with right hand in front of a plane mirror it will be seen in the mirror that your right ear is touched with ___.
3. The size of the pupil becomes ___ when you see in dim light.
4. Night birds have ___ cones than rods in their eyes.

Discuss the effects of deforestation on the following.

1. Wild animals 
2. Environment 
3. Villages (Rural areas) 
4. Cities (Urban areas) 
5. Earth 
6. The next generation

PQRS is a parallelogram (see the given figure). QM is the height from Q to SR and QN is the height from Q to PS. If SR = \(12\) cm and QM = \(7.6\) cm. Find: 

1. the area of the parallelogram PQRS 
2.  QN, if PS = 8 cm

Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence lie in the same plane.

State the laws of reflection.

A photograph of a bacteria enlarged 50,000 times attains a length of 5 cm. What is the actual length of the bacteria? If the photograph is enlarged 20,000 times only, what would be its enlarged length?

Find the missing values:

Base	Height	Area of triangle
15 cm	-	87 \(cm^2\)
-	31.4 mm	1256 \(mm^2\)
22 cm	-	170.5 \(cm^2\)

Fill in the blanks.

1. A place where animals are protected in their natural habitat is called ____ .
2. Species found only in a particular area is known as ____ .
3. Migratory birds fly to far away places because of ____ changes.

A machine in a soft drink factory fills 840 bottles in six hours. How many bottles will it fill in five hours?

Find the missing values:

So No	Base	Height	Area of parallelogram
a.	20 cm	-	246 \(cm^2\)
b.	-	15 cm	154.5 \(cm^2\)
c.	-	8.4 cm	48.72 \(cm^2\)
d.	15.6 cm	-	16.38 \(cm^2\)