Excel is both ubiquitous and easily understandable. Most people from every walk of life know how to use MS office and Excel spreadsheets. Students are also familiar with spreadsheets. Most students know how to use spreadsheets for data analysis. Besides basic use of Excel, some important aspects of spreadsheets are highlighted in this article. MS Excel can be used to visualize effects of various parameters in a physical system. It can be used as a simulating tool; simulation of wind data has been done through spreadsheets in this study. Examples of Lissajous figures and a damped harmonic oscillator are presented in this article.

The hyperfine (hf) structure of some spectral lines of the praseodymium atom has been investigated by the laser-induced fluorescence method in a hollow cathode discharge lamp. We report the discovery of 18 new energy levels of even parity and 22 new energy levels of odd parity and their magnetic dipole hf interaction constants A. Using these newly discovered levels, 268 lines were classified by means of laser spectroscopy, 97 of them by laser excitation and 171 via laser-induced fluorescence. In addition, 23 lines, observed in a Fourier transform spectrum, were classified by means of their wavenumbers and their hf patterns.

In this contribution, we present analysis of the total carbon contents and the major constituents in the Reference Coal sample of known concentration (SARM 20) and the Pakistani Thar Coal samples using laser induced breakdown spectroscopy (LIBS). A high-power Q-switched Nd:YAG Laser, (532nm, 5ns pulse width and 10 Hz repletion rate) was used to produce the Coal plasma in air and the optical emission spectra were registered using a HR 4000 spectrometer covering the wavelength region from 200 nm to 1100 nm. The emission spectrum of the laser produced plume contains the atomic lines of Ca, Si, Fe, Ti, Mg, Na, K, Li, Al and C along with the traces of Ba, Sr and Mn. The intensities of the observed spectral lines were corrected for self-absorption using the internal reference line self absorption correction method. The excitation temperature was calculated using the Boltzmann plot method and the Stark broadened H _α line profile was used to determine the electron number density. The calibration free LIBS (CF-LIBS) technique with a fixed slope method was utilized for the quantification of the carbon and other elements whereas, a laser-ablation time of flight mass spectrometer (LA-TOF-MS) was used to obtain the mass spectra of the same samples. All the elements identified in the optical emission spectrum have been also observed in the LA-TOF-MS mass spectrum. The results reveal that the Thar Coal samples collected from Sindh, Pakistan are comparable to the Reference Coal samples. It is further demonstrated that CF-LIBS and the LA-TOF-MS are efficient, reliable and complementary techniques for analyzing the Coal samples for the total carbon content, elements forming the ash and even for the detection of the trace elements at the ppm level.

We report the discovery of about 140 new energy levels of the neutral praseodymium atom, found by means of laser-induced fluorescence spectroscopy. Their energy has been determined with an uncertainty of 0.010 cm⁻¹ using a wave number calibrated Fourier-transform spectrum.