Question

a house as one bulb of 100w used for 10 hours a day the cost of electric energy used by the bulb in 30 days @ ruppes 3 per khw is

Answer 1

Energy used by Bulb is 100 watt

We know that

$\boxed{1\:kw=1000\:watt}$

So,

100 watt= 0.1 Kilo Watt

Now,

Time = 10 Hours

$\rule{200}{2}$

We know that

$\boxed{H= pt}$

Where H is energy, P is power consumed by the device and t is time for which the device runs.

Thus,

Energy consumption is equal to

$\boxed{0.1*10 = 1\:kwh}$

Energy consumption in 30 days will be equal to

$\boxed{1*30= 30\:kwh}$

$\rule{200}{2}$

Also,

We know that

$\boxed{1\:kwh=1\:unit}$

Cost of energy is Rs.3 per kwh

So,

Cost of electricity will be

$30 \times 3 = rs.90$

$\rule{200}{2}$

Therefore,

This cost of energy consumed will be Rs. 90

$\rule{200}{2}$

Answer 2

Answer:-

Given;

Power = 100Watt.

Time (in a day) = 10 hours.

We know that,

Energy Consumed = Power × Time

=> Energy Consumed = 100 × 10

=> Energy Consumed = 1000 Watt/hour.

Note:-

1 kWh = 1000 Wh.

=> Energy Consumed= 1 kWh.

Energy Consumed in 1 Day is 1 kWh.

=> Energy Consumed in 30 days = 30kWh.

Cost for 1 kWh = ₹3

=> Cost for 30 kWh = 3 × 30

=> Cost for 30 kWh = ₹90.