GUWAHATI CLUSTER CLASS 10 SCIENCE SET - 1

The reaction is repeated with magnesium powder in place of magnesium ribbon under the same conditions. What will happen?

• Rate of reaction increase
• Rate of reaction become steady
• rate of reaction decrease
• no effect on the rate of reaction.

A student was–performing an activity to prove the requirements for photosynthesis. During this activity, he kept two identical healthy potted plants A and B in dark for 72 hours. After 72 hours, he covered plant A and B by bell shaped jars separately. While covering the plants with separate bell jars, he kept KOH in the watch glass by the side of the plant in setup A and not in setup B. Both these setups were made air tight and were kept in light for 6 hours. Then, Iodine Test was performed with one leaf from each of the two plants A and B.Which of the following statements shows the correct results of Iodine Test performed on the leaf from plant A and B respectively?

• Blue - black colour would be obtained on the leaf of plant A
• Blue - black colour would be obtained on the leaf of plant B
• Red colour would be obtained on the leaf of plant A
• Red colour would be obtained on the leaf of plant B

An object is placed at a distance of 0.25m in front of a plane mirror. The distance between the object and image will be:

• 0.25m
• 1.0m
• 0.5m
• 0.125m

In which group of the organisms the food material is broken down outside the body?

• Mushroom, green plants, amoeba
• Yeast, mushroom, bread mould
• Paramecium, amoeba, cuscuta
• Cuscuta, lice, tapeworm

The focal length of a plane mirror is

• Zero
• Infinite
• 25cm
• -25 cm

Which of the following statements about the given reaction are correct? 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2 (i)Iron metal is getting oxidized. (ii)Water is getting reduced. (iii)Water is acting as a reducing agent. (iv)Water is acting as a oxidizing agent.

• (ii) and (iv)
• (iii) and (iv)
• (i), (ii) and (iii)
• (i), (ii) and (iv)

Methane gas released from waste water treatment plants can be used as a source of fuel. Which chemical equation represents combustion of methane to produce heat energy?

• CH4 + CO2→ 2O2 + 2H2O
• CH4 + 2O2→ CO2 + 2H20
• 2O2 + 2H2O → CO2 + CH4
• CO2 + 2O2→ CH4 + 2H2O

Every chemical reactions follow some Laws,which of the following law is not followed by the chemical reactions ?

• Law of conservation of molecules
• Law of conservation of atoms(elements)
• Law of conservation of charge
• Law of conservation of mass

Which of the following option shows the transport of oxygen to the cell correctly?

• Lungs →pulmonary vein →left atrium →left ventricle →aorta → body cells
• Lungs →pulmonary vein →right atrium →right ventricle → aorta → body cells
• Lungs →pulmonary artery →left atrium → left ventricle → vena cava → body cells
• Lungs →pulmonary artery →right atrium → right ventricle→ vena cava → body cells

People living at sea level has around 5 million RBCs per cubic millimeter of their blood, whereas those living at an altitude of 5400m have around 8 million RBCs per cubic millimeter of blood. This is because, at higher altitudes:

• People get pollution free air to breathe and more oxygen is available.
• People get more nutritive food, therefore more RBCs are formed.
• Atmospheric oxygen level is less and hence more RBCs are needed to deliver the required amount of oxygen to tissues.
• There is more UV radiation which enhances the production of RBCs.