Class 6 Science Chapter 7 MCQ

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

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.

The SI unit of measuring length is meter. 10,00,000 millimeter makes 1 kilometer. 1,00,000 centimeter makes 1 kilometer. 1,000 meter makes 1 kilometer. Thus, millimeter is the smallest unit of length and kilometer is the largest unit of length. But the SI unit of measuring length is “meter”. Note: When we measure the distance between celestial bodies (stars, galaxy, asteroids etc.) we use light year.

Here, are all the statements are incorrect. Hence, your answer will be option [D]. In option [A]: If an object moves fairly fast, then its movement or motion can be observed easily. In option [B]: If an object moves very slowly, then it becomes very difficult to observe its movement immediately. In option [C]: When an object is stationary it is said to be at rest.

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.

When an object turns or spins about a fixed axis, it is called rotational motion. When an object moves along a straight-line path it is called rectilinear motion. When a bicycle moves on a straight road, turning of bicycle wheel shows the rotational motion. And as it goes in a straight road, it exhibits the rectilinear motion.

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.

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].

In circular motion and object as a whole travel along a circular path but in rotational motion the object spins on its axis.

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.

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

The scientist all over the world have adopted “International System” of units or SI units which have a uniformity in the measurement of various physical quantities like length, mass and time etc. The SI unit of measuring length is “meter”. The symbol of meter is “m”. The SI unit of measuring mass is “kilogram” (kg) and the SI unit of measuring time is “second” (s)

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].