9. A bulb is rated at 330V- 110W. What do you think is its resistance? Three such bulbs burn for 5hrs at a stretch. What is the energy consumed? Calculate the cost in rupees if the rate is 70 paise per unit?
Answers
Explanation:
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Answer:
Resistance of 1 bulb = 990n
Total cost of energy consumed = Rs 1.155
Explanation:
Power = Work Done /Time
Work Done = Energy
Therefore,
Power = Energy/ Time
Energy = Vlt
Time = t
Power = VIt/t
Power = VI
According to the question,
V = 330 V
P = 110 W
t = 5 hrs
Number of bulbs 3
Cost of 1 unit of Energy = 70 paise
P = VI
I = P/V
1 = 110/330 A
| = 1/3 A
By Ohm's Law
V = IR
R = V/I
R = 330 ohm
R = 330 x 3 ohm
R = 990 ohm
Therefore , resistance of 1 bulb is 990 ohm
Energy = Vlt
E = Vit
E = 330 x x 5 Wh
E = 550 Wh
Therefore , energy consumed by 1 bulb is 550 Wh .
Energy consumed by 3 bulbs = 3 X Energy consumed by 1 bulb
Energy consumed by 3 bulbs = 3 X 550 Wh
Energy consumed by 3 bulbs = 1650 Wh
1 kWh = 1000 Wh
1 Wh = 1000 kWh
1650 Wh = 1650 kWh
1650 Wh = 1.65 kWh
1 Rupee = 100 paise
1 paise = 100 Rupee
70 paise = 70/ 100 Rupee
70 paise = Rs 0.7
Cost of 1 unit of Energy = Rs 0.7
Cost of 1 kWh of Energy = Rs 0.7
Cost of 1.65 kWh of Energy = Rs 0.7 X 1.65
Cost of 1.65 kWh of Energy = Rs 1.155
Therefore, the cost of 3bulbs is ₹1.155