Units and Measurements

Torque is the measure of rotational force and in the International System of Units (SI), it is expressed in Newton-meters (N·m), which combines force (Newton) and distance (meter).

The SI unit of volume is the cubic meter (m³), which is the volume of a cube with edges one meter in length. Options B, C, and D represent cubic centimeters, cubic millimeters, and cubic kilometers respectively, which are not the SI base unit but derived units.

The M.K.S. system (Meter-Kilogram-Second) was introduced by Giovanni Giorgi, who proposed this system as a practical set of units for scientific measurements. The other options are unrelated to the introduction of the M.K.S. system.

A wattmeter is specifically designed to measure the power in an electric circuit, which is the rate at which electrical energy is consumed or produced. The other instruments listed measure different quantities: a wavemeter measures frequency, and a viscometer measures viscosity.

One Coulomb is the charge of approximately 6.25×10^18 elementary charges (electrons). This is calculated by dividing 1 Coulomb by the charge of one electron (1.6×10^-19 C).

The SI unit of luminous intensity, which measures the perceived power of light, is the candela. Watt is a unit of power, Pascal is a unit of pressure, and Joule is a unit of energy, so they are incorrect in this context.

The farad (F) is the SI unit of capacitance, which measures a capacitor's ability to store charge per unit voltage. Therefore, option C is correct.

An Angstrom is a unit of length equal to 10^-10 meters, commonly used to measure atomic and molecular scales, such as wavelengths of light and sizes of atoms.

The SI unit of force is the Newton, which is defined as the force required to accelerate a one-kilogram mass by one meter per second squared.

A dyne is a unit of force in the centimeter-gram-second (CGS) system. It is defined as the force required to accelerate a mass of one gram at a rate of one centimeter per second squared.

A dyne is the unit of force in the centimeter-gram-second (CGS) system. It is defined as the force required to accelerate a mass of one gram at a rate of one centimeter per second squared.

A parsec is a unit of distance used in astronomy to measure large distances to objects outside our solar system, approximately equal to 3.26 light-years.

A Newton metre (N·m) is the SI unit of torque, which measures the rotational force applied at a distance from a pivot point. It is not used for substance, length, or work (work is measured in joules).

A light year is the distance that light travels in one year, making it a unit of distance, not time, energy, or mass.

The SI unit of pressure is the pascal (Pa), which is defined as one newton per square meter. Joule is a unit of energy, tesla is a unit of magnetic flux density, and henry is a unit of inductance.

A magnetometer is an instrument used to measure magnetic fields, including changes in the Earth's magnetic field. This makes option C the correct answer.

One light year is the distance light travels in one year, which is approximately 9.5×10^12 kilometers. This matches option C, making it the correct answer.

The SI unit of heat is the joule (J), which is the standard unit of energy in the International System of Units. Heat is a form of energy transfer, so it is measured in joules.

Cusec stands for cubic feet per second, which is a unit of flow rate or discharge. It measures the volume of water flowing past a point per second. This is widely used in hydrology and water resource management. One cusec equals one cubic foot of water flowing per second, approximately 28.3 liters per second.

A parsec is a unit of distance used in astronomy, equal to about 3.26 light-years. It measures the distance at which one astronomical unit subtends an angle of one arcsecond.

Since the volume of the wire remains constant, and volume = cross-sectional area × length, decreasing the radius to one-third reduces the area by (1/3)^2 = 1/9. To keep volume constant, length must increase by a factor of 9.

A Joule is a unit of energy, and a Pascal is a unit of pressure. Therefore, the analogy is correct: Joule relates to Energy as Pascal relates to Pressure.

A kilometre is a unit of distance, and similarly, a poundal is a unit of force. Thus, the analogy compares units to their respective physical quantities.

Ohm, Watt, Volt, and Ampere are all units related to electricity and electrical measurements, making 'Ampere' the most similar word among the options.