How does light tell us the temperatures of planets and stars?

Thermal radiation

31 December 2018 5,426 0 View

Why do astronomers think that the Universe is expanding?

Universe, red shift

11 December 2018 2,844 0 View

Physics: Why do we describe light by referring to its wavelength, but microwaves and radar pulses by referring to their frequency?

In physics, the description of the properties of light generally refers to its wavelength (nm), while in the range of microwaves and radio waves we refer to the frequency of a signal (e.g. kHz or...

03 March 2021 1,682 3 View

Is There Any Feasible Method To Test Fluorescent Compounds Other Than Fluorescence Spectrometers ??

Is There Any Feasible Method To Test The Efficiency Of Fluorescent Compounds Other Than UV Spectrometers ? Suggestions Would Be Appreciated !

02 March 2021 5,785 3 View

Is there any effect of different colours of light (white, red, yellow, blue etc.) on the rate of photosynthesis? If yes, why?

Light is inevitable for the process of photosynthesis reaction. Naturally sunlight plays the vital role for this process. Light may be of different colours like white, red, yellow, blue etc....

02 March 2021 7,890 2 View

What is Flat Lens Antenna?

28 February 2021 5,433 3 View

In an eye with Tyndall, does each dot correspond to an individual cell?

When you observe the presence of Tyndall in an inflamed eye: Does each of the small floating dots correspond to an individual cell or to an aggregate of cells? Does a conventional slit lamp have...

27 February 2021 6,326 2 View

Can impedance of antenna be less than 50 ohms?

I am simulating helix antenna in hfss, right now, giving excitation with 50 ohms port. When I see the results of Z parameter (real). It shows lower than 50 ohms. Do not understand, if it can be...

27 February 2021 4,218 7 View

How can I obtain time series data by country on night-time light (brightness) ?

Hi everyone, Please, how can I obtain time series data by country on night-time light (brightness) ? I've tried, but so far all I can find are maps. I am looking for numerical data, especially in...

24 February 2021 8,625 4 View

What are difference between laser diodes, simple light emitting diodes and power light emitting diodes when operated in the visible spectrum ?

I want to illuminate a scene (small space) using LED to capture photographs or videos of some tiny objects inside the space. But am not sure if I should use a Laser LED, or simple LED or power...

22 February 2021 4,240 4 View

Could the "incoming radiation (net radiation)" values be negative?

Could the "incoming solar radiation" values be negative? What is the difference between "global solar radiation" and "incoming solar radiation"? Which one might be measured negative values?

21 February 2021 7,726 9 View

How to interpret this FTIR spectrum of pyrolyzed hydrochar?

20 February 2021 2,840 3 View