BLE Questions of Science

Grade: - VIII (EIGHT) Full marks: 75
Subject: - Science TIME : 2:15 MINUT Pass marks: 30

All questions are compulsory. Students with their own answer will get priority.

Physics

1a. Differentiate between fundamental units and derived units with examples of each. Express one solar day into second. In which unit the length and the mass are measured in FPS system. [1.5+1+1=3.5]

b. What is the difference between MKS and CGS system of measurement? How are the area and the volume of an irregular object is measured? The unit of Velocity is called a derived unit. Why? [1.5+1+1.5=4]

2a.A man is guarding a house for one hour. Why it is not considered as work in science? Write any two difference between nuclear fusion and nuclear fission. What do you mean by the power of an electric bulb is 100W [1+2+1=4]

b. Prove that P=dgh where P is pressure exerted by a body, g is acceleration due to gravity and h is a depth of liquid. The pressure exerted by a liquid column of depth 0.5m on the base of its container is 5000Nm^-2.Find the density of the liquid. [2+2=4]

3a. What are the two types of work? What kind of energy transformation takes place in the following devices: [0.5+2=2.5]

a. hydro-electric power station c. a bullet fired from a gun b. a green plant d. heater

b. Prove the following formula where the symbols have their usual meanings. [2X2=4]

i. s = ut + 1/2 at²

ii. v² = u² + 2as

4a. A load of 1000N is lifter by using a second class lever. The load is at the distance of 5cm and the effort is at the distance of 20cm away from the fulcrum. If a 300N effort is applied to balance the load, calculate its MA, VR, and efficiency. A coolie of 40 kg weight carries 20 kg salt and climbs up 20 steps of 20cm each in 2 minutes. Calculate the work done by him and his power. [g=10m/s²] [2+2=4]

Chemistry

6a. Write any two difference between metal and non-metal. Write the name of metals which can be obtained from the following ores: [2+2.5=4.5]

a. argentite c. chalcopyrite e. calverite

b. bauxite d. hematite

b. Write any two uses of each of the following (Any 2) [1.5X2+1=4]

a. Washing Soda b. Glycerol c. Baking Soda

Write down the molecular formula of the following chemicals (Any 2)

a. Washing Soda b. Glycerol c. Baking Soda

7a. The given diagram is the atomic structure of element X. Look at the diagram and answer the following

i. What is the name of element? [0.5]

ii. Write the electron number, valency, nature of

element of the given element. [2]

iii. Differentiate between valence shell and valence

electron. [2]

b. Write any two differences between: (Any 2) [2+2=4]

a. hard water and soft water

b. washing soda and baking soda

c. permanent hardness and temporary hardness.

8a. What is temporary hardness of water? How can we soften it? Mention the name of method. [1+2=3]

b. Draw a neat and labeled diagram of the permutit process or ion exchange process. Define regeneration. [1+2+1=4]

Biology

8a. Look at the diagram given below and answer the following questions.

i. Label the A, B, C and D. [2]

ii. What is the name of the figure? Also define it [0.5+1=1.5]

b. Bacteria is both advantageous and disadvantageous to human beings.

Justify this statement. Also draw a neat and labeled diagram of bacterial cell. [2+2=4]

9a. Define pollination. What are the different types of pollination also explain them? [1+2=3]

b. Draw a neat and labeled diagram of bacteria. [2]

10a. Draw a floral diagram and also labeled any 4 parts it. [3]

b. Write any 2 difference between gynoecium and androecium. [2]

11a. Write the functions of the following: [1X4=4]

i. Calyx

ii. Corolla

iii. Stamen

iv. Pistil

b. Write the name of the virus which causes common cold and AIDS. Why virus is called obligatory parasite? Write any 1 living and 1 non-living characteristics of virus. [1+1.5+1=3.5]