List of top Questions asked in CBSE Class VIII

Draw a rough figure of a quadrilateral that is not a parallelogram but has exactly two opposite angles of equal measure.
What is Connie’s Christmas present? Why is it “the best Christmas present in the world”?
Solve and check result: \(8x + 4 = 3(x - 1) + 7\)
Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?
Write a paragraph in your own words on each of the following.
1. Preparation of soil
2. Sowing
3. Weeding
4. Threshing
Top surface of a raised platform is in the shape of a regular octagon as shown in the figure. Find the area of the octagonal surface.
raised platform of a regular octagon
 
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?
Subtract 4a – 7ab + 3b + 12 from 12a – 9ab + 5b – 3
Suppose 2 kg of sugar contains 9 x 106 crystals. How many sugar crystals are there in (i) 5 kg of sugar? (ii) 1.2 kg of sugar?
Factorise the following expressions 
  1.  \(7x - 42\) 
  2.  \(6p - 12q\) 
  3.  \(7a ^2 + 14a\) 
  4.  \(-16z + 20z ^3\) 
  5.  \(20l^ 2m + 30\, alm\) 
  6.  \(5x^ 2 y - 15xy^2\) 
  7.  \(10a^ 2 - 15b^ 2 + 20c^ 2 \)
  8.  \(-4a^ 2 + 4ab - 4 ca\) 
  9.  \(x ^2 yz + xy^2 z + xyz^2\)
  10.  \(ax^2 y + bxy^2 + cxyz\)
The lateral surface area of a hollow cylinder is 4224 cm2. It is cut along its height and formed a rectangular sheet of width 33 cm. Find the perimeter of rectangular sheet.
Suggest three measures to protect ourselves from lightning.
Describe the construction of a kaleidoscope.
Boojho stands at A just on the side of a plane mirror as shown in Fig. 
Boojho stands at A just on the side of a plane mirror
Can he see himself in the mirror? Also, can he see the image of objects situated at P, Q and R?
A 5 m 60 cm high vertical pole casts a shadow 3 m 20 cm long. Find at the same time -
(i) the length of the shadow cast by another pole 10 m 50 cm high
(ii) the height of a pole which casts a shadow 5 m long.
Factorise 
  1.  \(4p^ 2 - 9q ^2\) 
  2.  \(63a^ 2 - 112b ^2\) 
  3.  \(49x^ 2 - 36\) 
  4.  \(16x^ 5 - 144x^ 3\)
  5.  \((l + m)^ 2 - (l - m) ^2\) 
  6.  \(9x^ 2 y^ 2 - 16 \)
  7.  \((x^ 2 - 2xy + y^ 2 ) - z^ 2\) 
  8.  \(25a ^2 - 4b^ 2 + 28bc - 49c ^2\)
When a die is thrown, list the outcomes of an event of getting 
  1. (a) a prime number (b) not a prime number. 
  2. (a) a number greater than 5 (b) a number not greater than 5.
Give two differences between a zygote and a foetus.
Describe with the help of a diagram an instrument which can be used to detect a charged body.
Explain why sliding friction is less than static friction.
Find out the position of the image of an object situated at A in the plane mirror

(a) Find out the position of the image of an object situated at A in the plane mirror.
(b) Can Paheli at B see this image?
(c) Can Boojho at C see this image?
(d) When Paheli moves from B to C, where does the image of A move?
How many people and animals died in Yala National Park?
In the following statements, tick ‘T’ against those which are true, and ‘F’ against those which are false.
  1. Sound cannot travel in vacuum. (T/F)
  2. The number of oscillations per second of a vibrating object is called its time period. (T/F)
  3. If the amplitude of vibration is large, sound is feeble. (T/F)
  4. For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
  5. The lower the frequency of vibration, the higher is the pitch. (T/F)
  6. Unwanted or unpleasant sound is termed as music. (T/F)
  7. Noise pollution may cause partial hearing impairment. (T/F)
Factorise the following expressions. 
  1.  \(a^ 2 + 8a + 16 \)
  2. \(p^ 2 - 10p + 25 \)
  3. \(25m^2 + 30m + 9 \)
  4. \(49y^ 2 + 84yz + 36z ^2 \)
  5. \(4x^ 2 - 8x + 4 \)
  6. \(121b ^2 - 88bc + 16c ^2 \)
  7. \((l + m) ^2 - 4lm \) (Hint: Expand \((l + m) ^2 \) first)
  8.  \(a^ 4 + 2a ^2b ^2 + b^ 4\)
Complete the following table of products:
 

First monomial → Second monomial ↓

2x    

–5y

 3x2

– 4xy

7x 2 y

–9x 2 y 2

2x 

4x2

. . .

. . .

. . .

. . .

. . .

–5y

. . .

. . .

-15x2y

. . .

. . .

. . .

3x2

. . .

. . .

. . .

. . .

. . .

. . .

– 4xy

. . .

. . .

. . .

. . .

. . .

. . .

7x 2 y

. . .

. . .

. . .

. . .

. . .

. . .

–9x2 y2

. . .

. . .

. . .

. . .

. . .

. . .