Perform each conversion.

(a) 25 kWh to joules

(b) 249 cal to Calories

(c) 113 cal to kilowatt-hours

(d) 44 kJ to calories

Solution 53P

Here, we have to perform the unit conversion.

(a) 25 kWh to joules

We know,

kilowatt = kilowatt-hour / hour

P = E / t

watt = joule / second

W = J / s

Again,

1 kWh = 1000 W x (60 x 60 )s

= 36 x 105 Ws = 36 x 105 J

Thus,

25 kWh x (36 x 105 J/ 1 kWh) = 900 x 105 J

Therefore 25 kWh = 900 x 105 J = 9 x 107 J

(b) 249 cal to Calories

We know,

1 Cal = 4.184 Joule

Therefore, the conversion factor =

Thus,

249 cal x = 1041.82 Joule

Therefore,

249 cal = 1041.82 Joule = 1.041 kJ

(c) 113 cal to kilowatt-hours

We know,

1 cal = 4.184 watt-s

1000 watt = 1 kW

The conversion factors,

, , ,...