Question

A household uses 5 bulbs of 60 W each for 7 hours daily. If
one unit of electrical energy costs Rs 5, how much is the amount to be paid for the
usage of the bulbs every day?​

Answer 1

Answer:

• Rs 10.5 every day .

Explanation:

Solution:-

• Number of bulbs = 5
• Power of Each Bulb ,P = 60 W
• Time used for daily ,t = 7 hr.
• Rate of electrical energy (in unit) 5 per unit.

As we know that Energy consumed by any appliance is calculated by the product of power of appliances & the time for which the appliance is used.

• E = Pt

where,

• E denote Energy Consumed
• P denote Power of Bulb
• t denote time taken

Substitute the value we get

→ E = (5×60) × 7

→ E = 300 × 7

→ E = 2100 Wh

As we know that 1 unit = 1000 kWh

Therefore, 2100 Wh = 2100/1000 kWh = 2.1 kWh or Unit.

As it is given that the cost of electrical energy is 5 per unit.

Therefore, amount to be paid for the usage of bulb everyday is = 2.1 × 5 = 10.5

• Hence, the amount paid for the usage of bulbs every day is Rs10.5 .

Answer 2

Answer:

Given :-

• Total bulbs = 5 bulbs
• Energy of 1 bulb = 60 W
• Time = 7 hours per day
• Cost of 1 unit = ₹5

To Find :-

Amount for 1 day

Answer :-

As we know that

$\large \sf \: E = P \times T$

• E is the Energy consumed
• P is the Power
• T is the Time

$\large \sf \: E = (5 \times 60) \times 7$

$\large \sf \: E = 300 \times 7$

$\large \sf \: E = 2100 \: watt$

Now,

We may also write as

1000 kW = 1 kWh

2100 kW = 2.1 kWh

Now,

Finding bill

$\large \sf \: Amount \: for \: 1 \: day \: = 2.1 \times 5$

$\large \frak \red{Amount \: = Rs 10.5}$