Physics - Study Mode

[#176] Lux is the SI unit of
Correct Answer

(C) Intensity of illumination
(E) intensity of illumination

Explanation

Solution: Lux, unit of illumination (see luminous intensity) in the International System of Units (SI). One lux (Latin for “light”) is the amount of illumination provided when one lumen is evenly distributed over an area of one square metre.

[#177] Which of the following are used for accurately measuring very small time intervals ?
Correct Answer

(C) Atomic clocks

Explanation

Solution: An atomic clock is a clock device that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

[#178] Which of the following is the unit of Astronomical Distance ?
Correct Answer

(D) Parsec

Explanation

Solution: Parsec is the unit of Astronomical Distance.

[#179] What is unit of Astronomical distance ?
Correct Answer

(A) Light year

Explanation

Solution: Light year is the unit of Astronomical distance.

[#180] The SI unit of luminous emittance is :
Correct Answer

(A) Lux

Explanation

Solution: The lux (symbol: lx) is the SI unit of illuminance and luminous emittance. It is used in photometry as a measure of the intensity of light, with wavelengths weighted according to the luminosity function, a standardized model of human brightness perception.