Science revision

Grains or seeds are separated by the stalk by

• Threshing

• Sieving

• Winnowing

• Hand-picking

Winnowing is used to separate the grain from the

• Chaff

• Stalk

• Sediment

• Solvent

Hand-picking is preferred when

• The quantity of the mixture is small

• The unwanted substance is present in large quantity

• The unwanted substance can dissolve

• The size or colour of the unwanted substance is the same as the useful one

Condensation takes place only when

• Water vapour hits a cold surface

• Water vapour hits a hot surface

• A hot surface hits a warm surface

• Water is heated

Which of the following is soluble in water ?

• Chalk

• Sugar

• Sand

• Wood

The particles of the of the insoluble solid should be ___________ than the holes in the filtering device.

• Bigger

• Smaller

Chalk and sand are _____________ in water.

• Soluble

• Insoluble

The substance in which the solute dissolves is called a _____________.

• Solution

• Solvent

The quantity of a substance that can dissolve in ___________ water is much more as compared to ___________

• 1.hot

• Cold

• 2.hot

• Cold

Sugar in the ____________ form dissolves first.

• Powdered

• Solid