He efficiency of a steam power plant can be increased by bleeding off some of the steam that would normally enter the turbine and usingit to preheat the water entering the boiler. in this process, liquid water at 50oc and 1000 kpa is mixed with superheated steam at 200oc and 1000 kpa. if the plant operators want to produce a saturated liquid at 1000 kpa, what ratio of mass flow rates of water and superheated steam are required? [20]

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electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.