Answer:
A. The wavelength doubles but the wave speed is unchanged
Explanation:
The relationship between the period and wavelength is direct. Doubling the period of the oscillator will correspondingly double the wavelength but the wave speed is unaffected
Answer:

Explanation:
The charge on one object, 
The distance between the charges, r = 0.22 m
The force between the charges, F = 4,550 N
Let q₂ is the charge on the other sphere. The electrostatic force between two charges is given by the formula as follows :

So, the charge on the other sphere is
.
Answer:
The magnetic field is strongest at the center and weakest between the two poles just outside the bar magnet. The magnetic field lines are densest at the center and least dense between the two poles just outside the bar magnet.
Explanation: