Yes. Since the wavelength of the red line in the Hydrogen spectrum is 656.5 nanometer. This confirms the possibility of seeing the spectral line with the same wavelength in the absorption spectrum of hydrogen atoms. The Hydrogen spectrum has the lower limit of 656.5 nm which still includes 656.5 nm in the range.
The colour of the star and the brightness.
Explanation:
Mass of the ball, m = 0.058 kg
Initial speed of the ball, u = 11 m/s
Final speed of the ball, v = -11 m/s (negative as it rebounds)
Time, t = 2.1 s
(a) Let F is the average force exerted on the wall. It is given by :


F = 0.607 N
(b) Area of wall, 
Let P is the average pressure on that area. It is given by :


P = 0.202 Pa
Hence, this is the required solution.
Without air resistance, both balls reach the ground at the same instant.
Neither horizontal motion nor weight affects vertical motion.
True if you actually did it. false if you didn't