Test: Measurements And Experimentation - Class 9 MCQ

The pound is not a metric unit; it is part of the imperial system. Kilogram, gram, and milligram are all metric units used to measure mass, with the kilogram being the base unit in the S.I. system.

The screw gauge is designed for high precision measurements, capable of measuring small lengths with an accuracy of up to 0.001 cm. Its design allows for finer adjustments compared to other instruments.

The least count represents the smallest increment that an instrument can measure accurately. A smaller least count indicates a more precise instrument, allowing for more detailed measurements.

A zero error occurs when the reading of a measuring instrument does not start from zero when the instrument is at rest. This discrepancy can be corrected by adjusting the reading based on the error.

A unit serves as a standard reference to express how many times it fits into the quantity being measured. Every measurement comprises a numerical value and a unit, which together convey the magnitude of the physical quantity.

The effective length of a pendulum is defined as the distance from the point of suspension to the center of gravity of the bob. This measurement is crucial in calculating the pendulum's oscillatory behavior.

Pressure is defined as force applied per unit area (P = F/A). This relationship shows how much force is distributed over a given area, which is crucial in fields such as physics and engineering.

The kilogram is a fundamental unit in the S.I. system, representing mass. In contrast, square meter, newton, and joule are derived units, as they are expressed in terms of fundamental units.

The S.I. unit for measuring temperature is Kelvin (K). This unit is essential in scientific contexts where absolute temperature is required, unlike Celsius and Fahrenheit, which are relative scales.

The joule (J) is the derived unit for energy in the S.I. system, defined as the work done when a force of one newton moves an object one meter. Understanding this relationship is key in physics.

The relationship between frequency (f) and time period (T) is defined as f = 1/T, meaning that frequency is the reciprocal of the time period. This relationship is fundamental in wave mechanics and oscillation studies.

Prefixes are used in the S.I. system to represent multiples or fractions of units, making it easier to express large or small quantities, such as kilometer (10^3 meters) or millimeter (10^-3 meters).

The current definition of the meter is based on the distance light travels in a vacuum in 1/299,792,458 of a second. This definition provides a universal standard that is consistent across time and technology.

Increasing the length of a simple pendulum increases its time period. This relationship is crucial in understanding oscillatory motion, with the time period being proportional to the square root of the length.

A suitable unit must have a clear and unambiguous definition to ensure consistency and accuracy in measurement. Ambiguity would lead to confusion and errors in interpretation.