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Class 10 Class 12
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?

Given,

Volume of the tank, V = 30 m

Time of operation, t = 15 min

= 15 × 60

= 900 s

Height of the tank, h = 40 m

Efficiency of the pump, η = 30 %

Density of water, ρ = 103 kg/m

Mass of water, m = ρV = 30 × 103 kg

Output power can be obtained as,

P0 =

= 30 × 103 × 9.8 ×

=  13.067 × 10
3 W

For input power Pi,, efficiency η, is given by the relation,

η ==  30%

Pi =

= 0.436 × 105 W

=  43.6 kW, is the electric power consumed by the pump.
201 Views

Is work a scalar or a vector quantity?

Work is dot product of two vectors. i.e. .

And dot product is a scalar quantity. Therefore, work is a scalar quantity.
1450 Views

Define the unit joule.

Work done is said to be one joule if one newton of  force displaces the body through a distance of one meter in the direction of applied  force .
799 Views

What are different units of energy?

The different units of energy are :

(i) Joule
(ii) Erg
(iii) eV
(iv) KWh
(v) Calorie.

804 Views

What is watt?

SI unit of power is Watt.
773 Views

Define watt.

Power is said to be one watt if one joule of work is done in one second.
860 Views