Question

An electrical equipment rated 100W operates 4 hours per day.
What is the cost of energy to operate it for 30 days at Rs.4
per KWh ?​

Answer 1

Answer:

• Cost of operating energy for 30 days would be Rs. 48.

Explanation:

Given,

• Power rating of Electrical equipment, P = 100 W
• time for which it is used daily = 4 hours
• Number of days for which it is used = 30 days
• Rate of energy consumed = Rs. 4 per kWh

To find,

• Cost of operating equipment for 30 days =?

Solution,

Since, electrical appliance is used 4 hours daily for 30 days

therefore,

→ Total number of hours it is used for = 4 × 30

→ Total number of hours it is used for = 120 Hrs

Now,

Using formula ; Energy = power × time

→Total energy consumed = 100 W × 120 hrs

→ Total energy consumed = 12000 Wh

→ Total energy consumed = 12 kWh

Further,

Rate of energy consumed is Rs. 4 per kWh

so,

→ Cost of energy operated in 30 days = 12 × 4

→ Cost of energy operated in 30 days = 48 Rs.

Therefore,

• Cost of operating energy for 30 days would be Rs. 48.

Answer 2

$\huge{\mathbb{ANSWER}}$

　　　　　　　　　　　　　　　　

Power = 100 W = 0.1 kW

Time = 4 hours/day

　　　　　　　　　　　　　　　　

$\boxed {\rm{Energy = Power×Time}}$

$\sf Energy = 0.1 \times 4$

$\underline{ \sf Energy = \red{0.4 \: kWh}}$

　　　　　　　　　　　　　　　　　　　　　

$\sf Energy \: consumed \: in \: 1 \: day = 0.4 \: units.$

$\sf Energy \: consumed \: in \: 30 \: days = 30 \times 0.4 \: units.$

$\sf \underline{ Energy \: consumed \: in \: 30 \: days = \red{12 \: units}. }$

　　　　　　　　　　　　　　　　

$\sf Cost \: of \: 1~kWh\: energy = ₹4$

$\sf Cost \: of \: 12~kWh\: energy = ₹(4×12)$

$\therefore~ \underline{ \underline {\sf {Cost \: of \: 12~kWh\: energy = \red{₹48}}}}$