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Class 11
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a pump on the ground floor of a building can pump...

Question:
A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m³ in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump?

Answer:

Volume of the tank, V= 30 m³

Time of operation, t = 15 min = 15 × 60 = 900 s

Height of the tank, h= 40 m

Efficiency of the pump, n = 30%

Density of water, p = 10³kg/m3

Mass of water, m= pV= 30 ×10³ kg

Output power can be obtained as:

P₀ = work done / Time = mgh / t

= 30 x 10³ x 9.8 x 40 / 900 = 13.067 x 10³W

For input power Pi,, efficiency n is given by the relation:

n = P₀ / P_i = 30%

P_i = 13.067 / 30 x 100 x 10³

= 43.6 kW

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Question:
A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m³ in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump?

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Question: A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m3 in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump?

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Question:
A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m³ in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump?