Class 6 Science Chapter 7 MCQ

Here, are all the statements are correct. Hence, your answer will be option [D].

The motion which repeats itself after regular intervals of time, is called periodic motion. When an object moves along a circular path, it is called circular motion. The movement of seconds’ hand of a watch is repeated after regular intervals of time, so the motion of seconds’ hand of a watch is an example of periodic motion. Similarly, the movement of the seconds’ hand of a watch or clock on the dial is an example of circular motion. As the watch does not move from one place to another by itself but the hands of watch or clock keep on rotating on its dial.

The distance between Delhi and Mumbai is expressed in kilometer because other units like meter, centimeter and decameter are so small to express this big distance.

Motion in a straight line is called rectilinear motion. In other words, when an object moves along a straight-line path it is called rectilinear motion. The motion will not be exhibited by the moon moving around the earth is rectilinear motion. And rest of three motions are exhibit by the moon.

We have to convert the height of 1.56 m into mm. Now, we know that: 1 meter = 1000 mm So, 1.56 m = 1000 x 1.56 mm = 1560 mm Thus, a height of 1.56 m is equal to 1560 millimeter

The thickness of a coin or a thin wire is a very small length which is much smaller than even centimeter. So, it is inconvenient to express very small length in terms of centimeters. Thus, to express the thickness of a coin or a thin wire we use millimeter as the unit of length. The very small length is expressed in still smaller units called a “millimeters”.

Here, are all the statements are correct. Hence, your answer will be option [D].

A communication satellite is stationed in an orbit high above the earth which shows three types of motion rotational motion, periodic motion and circular motion but not exhibit rectilinear motion.

Paheli moves in a straight path from A to C and from C to A. So, the motion is rectilinear, further Paheli moves in a periodic motion because she makes 5 rounds in the same way and crosses point B in each round, after a regular a time interval. So, her motion is rectilinear and periodic.

As we know that: 1000 meter makes 1 kilometer 1 meter = 1/1000 kilometer 1425 meter = 1/1000 x 1425 kilometer = 1.425 kilometer Thus, a distance of 1425 meter is equal to 1.425 kilometer.

When a ball is moving on the ground, it is rotating as well as moving forward on the ground. So, a ball rolling on the ground has two types of motion, rotational motion as well as a rectilinear motion.

A pencil or a notebook has small length which is much smaller than a meter. It is inconvenient to express such a small length in terms of meter. So, the length of small objects is measured in centimeter. Thus, in order to measure the length of a pencil or notebook, we use centimeter as the unit of length. A centimeter is one-hundredth of a meter.

We know that, 1 hour = 60 x 60 = 3600 seconds (Thus, 1 minutes = 60 seconds and 60 minutes make an hour) 24 hour = 3600 x 24 = 86,400 seconds

If we consider a merry-go-round as a whole, then it shows rotational motion because it turns on an axle. But the outer part of merry-go-round (on which children sit) shows circular motion. So, a merry-go-round has two types of motion at the same time, rotational motion and circular motion.

Here, are all the statements are correct. Hence, your answer will be option [D].

Here, are all the statements are correct. Hence, your answer will be option [D].

The various types of devices which are commonly used for measuring length are meter scale and measuring tape. If the object is round then we have to use a measuring tape for making measurement of length. As the girth of a tree can be measured only by using a measuring tape because a measuring tape can be bent around the tree. And plastic ruler, a meter scale or a meter rod is made of metal and cannot be bend at all.

All the reasons are correct. Hence, your answer will be option [D].

The earth moves around the sun, so it has circular motion. The earth repeats its motion around the sun after regular intervals of time (means one year), so it has periodic motion and the earth rotates on its axis, so it has also rotational motion. Thus, the earth has three types of motion at the same time, circular motion, periodic motion and rotational motion.

In the beginning of 19th century, the invention of steam engine introduced a new source of power to run transport vehicles. Steam engines were used to pull trains on railroads or railway tracks for carrying people and goods from one place to another. Steam engines were also used to run ships in the beginning. The steam engine is called external combustion engine because the fuel or coal for making steam was burnt outside the engine.

The compass was invented in China during the Han Dynasty between the 2nd century BC and 1st century AD where it was called the “south-governor”. The Chinese first used compasses not for navigation, but for spiritual purposes. They used the magnetic devices to organize buildings and other things according to feng shui, the ancient practice of harmonizing an environment according to the “laws of Heaven.”

Here, are all the statements are correct. Hence, your answer will be option [D].

The screw undergoes two kinds of motion that is periodic motions and circular motion.

Here, are all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].