If the top of the oil is 25.0 cm above the bottom of the tube, what is the height of the top of the water above the bottom of the tube?

This question is incomplete, the complete question is;

In the Manometer tube in the figure below, the oil in the right-hand arm is olive oil of density 916 kg/m³

If the top of the oil is 25.0 cm above the bottom of the tube, what is the height of the top of the water above the bottom of the tube?

the height of the top of the water above the bottom of the tube is  22.9 cm

Explanation:

from the diagram

P_oil = 916 kg/m³

h_oil = 25 cm = 0.25 m

p_water = 1000 kg/m³

Now, in equilibrium;

pressure at  p due to water = pressure at p due to oil

⇒h_water × p_water × g = h_oil × p_oil × g

h_water = h_oil × p_oil × g / p_water × g

h_water = (0.25 × 916) / 1000

h_water = 0.229 m ≈ 22.9 cm

Therefore the height of the top of the water above the bottom of the tube is  22.9 cm

a electromagnetic waves

the bal will not change its velocity.