Question

An electric heater of 1000w is used for 3 hours a day. What is the cost of using it for a month of 25 days if 1 unit cost 4 rupees?

Answer 1

p = 1000w

= 1000/1000 = 1kw

t = 3 hrs per day

E = p*t

= 1*3 = 3kwh

In 25 days,

= 3*25 = 75kwh

Cost of 1kwh = Rs 4

Cost of 75kwh = 75*4 = Rs 300

Answer 2

Given :

Power of electric heater , P = 1000 W = 1 kW .

Hourly used per day , $h=3 \ hr$ .

Number of days it used , n = 25 .

Cost per unit , c = 4 Rs .

To Find :

The cost of using it for a month of 25 days .

Solution :

Daily consumption , $d=1\times 3= 3\ kW. h$

So , monthly consumption ,

$D=d\times 25\\D=3\times 25=75\ kW.h$

Therefore , cost per month is :

$C=D\times 4\\C=75\times 4\ Rs\\C=300\ Rs$

So , the cost of using it for a month of 25 days is 300 Rs .

Learn More :

Power and Energy

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