You measure the emission spectrum of an atom that you suspect to be hydrogen. You have noabsolute calibration of the wavelength, but theratiosof the first 3 wavelengths in the seriesthat you measure are 1 : 0.741 : 0.661. Which series is this (e. g. Lyman, Balmer, Paschen, Brackett...)

On a average work day more than work place firs are reorted

If a particle moves along a path such that r : (3 sin t) m and ? : 2t rad, where t is in seconds. what is the particle's acceleration in m/s in 4 seconds? a)- 16.43 b)- 16.29 c)- 15.21 d)- 13.79

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?