Atomic Spectra

From the above chart it is clear that Balmer series lies in the visible region of the electromagnetic spectrum.

In the hydrogen atom, the transition from to corresponds to the shortest wavelength of the Paschen series. The Paschen series occurs when the electron transitions to from a higher energy level. The shortest wavelength occurs when the transition is from to .
Thus, the correct answer is .

In the Brackett series, the transitions occur between higher energy levels. The minimum wavelength in the Brackett series corresponds to the transition from to .
Thus, the correct pair for the minimum wavelength in the Brackett series is: Therefore, the correct answer is .

In simple harmonic motion (SHM), the magnitude and direction of acceleration change continuously. The acceleration is proportional to the displacement from the equilibrium position, and it is always directed towards the equilibrium position. The magnitude of acceleration is given by: where:
- is the angular frequency,
- is the displacement from the equilibrium position.
Step 1: Understanding acceleration in SHM.
In SHM, acceleration changes its direction as the object moves back and forth. When the object is at the maximum displacement, the acceleration is at its maximum and directed towards the center. When the object is at the equilibrium position, the acceleration is zero.
Step 2: Conclusion.
Therefore, the correct answer is (A), as in simple harmonic motion, both the magnitude and direction of acceleration change continuously.
Final Answer:} (A) Simple harmonic motion

The force that holds the nucleons (protons and neutrons) together in the nucleus of the atom is the
strong nuclear force.
Explanation:
The strong nuclear force is one of the four fundamental forces of nature and is the strongest of them. It acts between the nucleons (protons and neutrons) and binds them together to form the nucleus. The strong nuclear force is attractive at short distances (about ), and it is much stronger than the electrostatic force that tends to push the positively charged protons apart. Thus, the answer is: