Science Revision Worksheet

The process of separating lighter husk particles from heavier grains is __________________.

• sieving

• winnowing

• handpicking

• threshing

Answer explanation

The process of winnowing involves separating lighter husk particles from heavier grains using wind or air. This method effectively removes unwanted materials, making 'winnowing' the correct choice for the given question.

Which of the following mixtures would you be able to separate using the method of filtration?

• oil in water

• cornflakes in milk

• Mud in water

• sugar in milk

Answer explanation

Filtration can separate solid particles from a liquid. In this case, 'Mud in water' contains solid mud particles that can be filtered out, while the other mixtures either do not contain solids or are homogeneous solutions.

The muscles are attached to the bones by strong fibres called __________.

• cartilage

• ligaments

• bones

• tendons

Answer explanation

The correct answer is 'tendons' because tendons are the strong fibers that connect muscles to bones, allowing for movement. Cartilage and ligaments serve different functions in the body.

The shape of body of fish is __________________________.

• elliptical

• streamlined

• oval

• pentagonal

Answer explanation

The shape of a fish's body is streamlined, allowing it to move efficiently through water. This design reduces drag and helps fish swim faster, making 'streamlined' the correct choice over other options like elliptical or oval.

In the following questions, two statements are given – one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to this question from the codes (a), (b), (c) and (d) as given below: Assertion: Fish have gills. Reason: Gills help fish to use oxygen dissolved in water.

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer explanation

Both the Assertion (A) and Reason (R) are true. Fish possess gills, which are essential for extracting oxygen from water, making R the correct explanation for A.

Assertion: A ball rolling on a rough surface stops faster than on a smooth surface. Reason: Friction is greater on rough surfaces compared to smooth surfaces.

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer explanation

Both the assertion and reason are true. A ball stops faster on a rough surface due to greater friction, which provides more resistance against the ball's motion, making R the correct explanation for A.

Assertion: Magnetic poles always exist in pairs. Reason: If you break a magnet, the north and south poles will separate.

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer explanation

Both the assertion and reason are true. The assertion states that magnetic poles exist in pairs, and the reason explains that breaking a magnet results in the formation of new north and south poles, supporting the assertion.

The SI unit of mass is _____________ .

• metre

• second

• kilogram

• kelvin

Answer explanation

The SI unit of mass is the kilogram, which is the standard unit used to measure mass in the International System of Units (SI). Other options like metre, second, and kelvin represent different physical quantities.

________________ is the example of natural magnet.

• bronze

• copper

• nickel

• magnetite

Answer explanation

Magnetite is a naturally occurring mineral that exhibits magnetic properties, making it a natural magnet. In contrast, bronze, copper, and nickel are not natural magnets.

A freely suspended magnet always rests pointing in the north-south direction.

• attractive property

• directive property

• repulsion property

• none

Answer explanation

A freely suspended magnet aligns itself along the Earth's magnetic field, which is why it points north-south. This behavior is known as the directive property, distinguishing it from attractive or repulsive properties.