Which of the following instrument is used for measuring the illumination level of light?
Lux meter
Illumination Level Measurement Explained
The question asks about the specific instrument used to measure the illumination level of light. Understanding the different types of meters helps identify the correct tool for this task.
Lux Meter Function
A Lux meter, also commonly known as a light meter, is a specialized instrument designed to measure illuminance. Illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, or how well lit a surface is. The standard international (SI) unit of illuminance is the lux (lx). Therefore, an instrument specifically named after this unit is the most direct tool for measuring illumination levels.
- Principle: Lux meters typically use a photodiode to convert light into an electrical current. The current generated is proportional to the intensity of the light, which is then processed and displayed as an illuminance value in lux.
- Applications: Lux meters are widely used in various fields, including photography, film, lighting design, horticulture, environmental monitoring, and workplace safety to ensure adequate lighting levels.
Analysis of Other Options
Let's consider why the other options are not suitable for measuring the illumination level of light:
- Frequency meter: This instrument is used to measure the frequency of an AC electrical signal, typically in Hertz (Hz). It has no function related to light or its illumination level.
- Harmonic analyzer: A harmonic analyzer is used to identify and quantify the harmonic components present in an electrical waveform. It's crucial for power quality analysis in electrical systems, but it does not measure light illumination.
- Digital multimeter: A digital multimeter (DMM) is a versatile electronic measuring instrument that combines several measurement functions in one unit. It can measure voltage (Volts), current (Amperes), resistance (Ohms), and sometimes capacitance or temperature. While extremely useful for general electrical measurements, a standard digital multimeter does not have the capability to measure the illumination level of light directly. Some specialized multimeters might have light sensor attachments, but the core instrument itself isn't designed for it.
Summary of Instruments and Their Uses
| Instrument | Primary Measurement | Unit |
|---|---|---|
| Lux meter | Illumination level of light (Illuminance) | Lux (lx) |
| Frequency meter | Frequency of AC signals | Hertz (Hz) |
| Harmonic analyzer | Harmonic content in electrical waveforms | % (of fundamental), Volts, Amperes |
| Digital multimeter | Voltage, Current, Resistance, etc. | Volts (V), Amperes (A), Ohms ($\Omega$) |
Based on the analysis, the Lux meter is the correct and specific instrument for measuring the illumination level of light, as it measures illuminance in lux.
Important Questions from Plane Table Survey
Which of the following represents the CORRECT order of setting up a plane table?
After fixing the plane table to the tripod, the main operations which are needed at each plane table station are:
i) leveling
ii) orientation
iii) centering
The correct sequence of these operations is-In plane tabling the instrument used to measure horizontal and vertical distances directly is known as
What is the purpose of conducting the resection method in the plane table surveying?
The principle of plane table survey is:
