Correct Answer - Option 2 : 0.4 bar, 4.077 m of water, 0.299 m of mercury

**Concept:**

Pressure = 40 kPa

1 bar = 10^{5} Pa ⇒ 100 kPa

⇒ 40 kPa = 0.4bar

In terms of water head:

P = ρgh

For water, ρ = 1000 kg/m^{3}, g = 9.81, P = 40 kPa

\( \Rightarrow h = \frac{{40 × {{10}^3}}}{{1000 × 9.8}} = 4.08\;m\;\)of water

In terms of Mercury head:

For Mercury, ρ = 13.6 × 10^{3} kg/m^{3}, P = 40 kPa

\( \Rightarrow h = \frac{{40 × {{10}^3}}}{{13.6 × 1000 × 9.8}} = 0.30~m\;of\;mercury\)