Question

❤Hi friends ❤

1.The power output of an engine is 3 kW .How much work does the engine do in 20s.

2.An electric heater uses 600 Kj of electrical energy in 5 mins . Calculate it's power rating.?

3.Five electric fans of 120 watts each are used for 4 hours , Calculate the electrical energy consumed in kilowatt-hour .

4.How much electrical energy in joules does a 100 watt lamp consume ..

a.in 1 second
b.in 1 minute.


_________________________

Answer 1

here, you have to use only one formula .
power = energy /time.

Let see :
(1) power of engine = 3 kW = 3000 W
time = 20 sec
energy = ?
by formula ,
energy = power × time
= 3000 × 20 J
= 60000 J
= 6 × 10⁴ J

(2) energy = 600 KJ
time = 5 min
power = ?
by formula,
power = energy/ time
= 600 × 10³/5 × 60
= 2 × 10³ J

(3)power of each electric fan = 120 W
total power consume by 5 fans = 5 × 120 W = 600 W = 0.6 KW
time = 4 hr
by formula,
energy = power × time
= 0.6 × 4 = 2.4 KWh

(4) (a). power of lamp = 100 W
time = 1 sec
energy = power × time
= 100 × 1
= 100 J

(b) time = 1 min = 60 sec
energy = 100 × 60 J
= 6000 J

Answer 2

Hey buddy !!!

Here's the answer you are looking for

Please see the attached file for your answer


★★ HOPE THAT HELPS ☺️ ★★