Free Measurements MCQs with Answers

111. In MKS system, the unit of current is:

• A. Ampere
• B. Volt
• C. Coulomb
• D. Ohm

Explanation: The ampere (A) is the unit of electric current in the MKS system. One ampere is defined as one coulomb of electric charge flowing per second through a conductor. It is a fundamental unit in the International System of Units (SI) and is used to measure the rate of flow of electric charge in a circuit.

112. The new era of modern physics began near the end of:

• A. 16th Century
• B. 17th Century
• C. 18th Century
• D. 19th Century

Explanation: The late 19th century marks the beginning of the new era of modern physics. This period saw the formulation of classical electromagnetic theory by James Clerk Maxwell, the development of thermodynamics, and the groundbreaking work of physicists like Michael Faraday. However, the true turning point came with the advent of quantum mechanics and the theory of relativity in the early 20th century, initiated by physicists such as Max Planck, Albert Einstein, Niels Bohr, and others.

113. The theory of relativity was produced in 1905 by:

• A. Einstein
• B. Maxwell
• C. Young
• D. Kelvin

Explanation: Albert Einstein, a German physicist, introduced the theory of relativity in two parts: the special theory of relativity in 1905 and the general theory of relativity in 1915. The special theory of relativity, encapsulated in the famous equation E=mc², revolutionized our understanding of space, time, and energy. The general theory of relativity extended these ideas to include gravity and described it as the curvature of spacetime caused by mass and energy.

114. Which of the following is not a fundamental quantity?

• A. Length
• B. Temperature
• C. Electric charge
• D. Ampere

Explanation: Ampere is not a fundamental quantity. It is a derived quantity. Ampere is the unit of electric current, and electric current is defined in terms of the flow of electric charge per unit time. In the SI system, the ampere is defined in terms of the elementary charge and is not considered a fundamental quantity.

115. The unit of torque in SI units is:

• A. Meter
• B. Newton
• C. Kilogram
• D. Newton.meter

Explanation: The newton·meter (N·m) is the SI unit of torque. Torque is the rotational equivalent of force, and it is calculated by multiplying the force applied to an object by the distance from the axis of rotation. The formula for torque is given by Torque = Force × Distance. In this formula, force is measured in newtons, and distance is measured in meters, resulting in the unit newton·meter for torque.

116. In International system of units, called SI units, the unit of mass is:

• A. Pound
• B. Gram
• C. Kilogram
• D. Quintal

Explanation: The kilogram (kg) is the SI unit of mass. It is defined as the mass of the international prototype of the kilogram, which is a platinum-iridium alloy cylinder kept at the International Bureau of Weights and Measures (BIPM) in France. The kilogram is the fundamental unit of mass in the SI system.

117. In SI system, the unit of length is:

• A. Millimetre
• B. Centimetre
• C. Meter
• D. Kilometer

Explanation: The meter (m) is the base unit of length in the SI system. It is defined as the distance traveled by light in a vacuum during a specific time interval. The meter is widely used for measuring various lengths, from everyday objects to astronomical distances.

118. In SI system, the unit of time is:

• A. Second
• B. Minute
• C. Hour
• D. Day

Explanation: The second (s) is the base unit of time in the SI system. It is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom. The second is the fundamental unit for measuring time intervals and is used in various scientific, technological, and everyday contexts.

119. In SI system, the unit of temperature is:

• A. Kelvin
• B. Degree centigrade
• C. Degree Fahrenheit
• D. Degree Celsius

Explanation: The kelvin (K) is the base unit of temperature in the SI system. It is defined based on the properties of matter and is the unit used for scientific and international temperature measurements. The Kelvin scale is an absolute temperature scale with 0 K representing absolute zero, the lowest possible temperature where particles have minimal thermal motion.

120. In SI system, the unit of energy is:

• A. Calorie
• B. Joule
• C. Erg
• D. Dyne

Explanation: The joule (J) is the SI unit of energy. It is defined as one newton-meter, which is the work done when a force of one newton acts over a distance of one meter. The joule is a fundamental unit and is widely used in scientific and engineering contexts to measure various forms of energy, such as kinetic energy, potential energy, and thermal energy.