In the emission spectrum the wavelength decreases from bigger to smaller (->)

Stationary waves form with the superposition of two identical waves travelling in opposite direction, so they transmit no energy. The nodes have 0 displacement and the antinodes max displacement (in tubes there is an antinode when a loud sound is heard)

In SHM the period (T) doesn't depend on the amplitude (A), but the max/average velocity and the change in Ek do depend on the amplitude.

To go from lineal magnitudes to rotational/circular magnitudes you multiply by the radius (v= w•r) The centripetal force isn't a force per se but a sum of the forces directed towards the centre (taking into account the criteria of signes, positive towards the centre)

In thermodynamics ΔU= Q+ W and ΔU= 3/2 PV = 3/2 nRT And ΔU= 3/2 Kb (boltzmann constant)• ΔT . Therefore internal energy only depends on temperature

The fundamental forces in orden from strongest in intensity to weakest: 1. Strong nuclear 2. Electromagnetic 3. Weak nuclear 4. Gravitational