set 1 MCQ Questions & Answers Detailed Explanation

Answer: (a)

Since displacement is always less than or equal to distance but never greater than distance.

Hence, the numerical ratio of displacement to the distance covered is always equal to or less than one.

Answer: (b)

Fundamental unit:

The SI unit of a fundamental quantity is called a fundamental unit.

There are 7 fundamental quantities and their fundamental units.
The fundamental quantities are Length, Mass, Time, Electric Current, Thermodynamic Temperature, Luminous Intensity, etc.
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Also know,

Fundamental Quantity:

An independent physical quantity that cannot be expressed in terms of other physical quantities is called fundamental quantity.
They are conventionally chosen. It is used as a base to get other derived quantities by combining them.

Supplementary units:

The units that are used along with base units to form derived units in the International System are called supplementary units.

Explanation for the question:

meter (m), kilogram (Kg) and second (s) are the fundamental units of fundamental quantities Length, Mass and Time respectively.

Where Newton (N) is a Derived Quantities.

Answer: (a)

Answer: (a)

A dimensionless quantity (also known as a bare, pure, or scalar quantity as well as a quantity of dimension one).

It is a quantity to which no physical dimension is assigned, with a corresponding SI unit of measurement of one (or 1), which is not explicitly shown. Dimensionless quantities are widely used in many fields, such as mathematics, physics, chemistry, engineering, and economics. Dimensionless quantities are distinct from quantities that have associated dimensions, such as time (measured in seconds).

Dimensionless units are dimensionless values that serve as units of measurement for expressing other quantities, such as radians (rad) or steradians (sr) for plane angles and solid angles, respectively. For example, the optical extent is defined as having units of metres multiplied by steradians.

Answer: (a)

A light-year, alternatively spelt lightyear, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometres (9.46×1012 km), or 5.88 trillion miles (5.88×1012 mi).

As defined by the International Astronomical Union (IAU), a light-year is a distance that light travels in a vacuum in one Julian year (365.25 days).

Because it includes the time-measurement word "year", the term light-year is sometimes misinterpreted as a unit of time.

The way to calculate the light-year distance is henceforth explained:

299792458 x 60 x 60 x 24 x 365.25

Where:

• 299 792 458 is the number of meters light travels in one second.
• 60 is the number of seconds in a minute.
• The other 60 is the number of minutes in an hour.
• 24 is the number of hours in a day.
• 365.25 is the number of days in a Julian year.

Answer: (c)

Light-year is the distance light travels in one year.

Light zips through interstellar space at 186,000 miles (300,000 kilometres) per second and 5.88 trillion miles (9.46 trillion kilometres) per year.