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A device consuming 15 W is switched on for 6 hours a day and another device consuming 20 W is operated for 3 hours a day. The minimum Ah rating of a 12 V battery supplying power to the devices is
  • a)
    12.5 Ah
  • b)
    35 Ah
  • c)
    15 Ah
  • d)
    20 Ah
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
A device consuming 15 W is switched on for 6 hours a day and another d...
For 15 W device,
Current, I = 15/12 Amp
Amp-Hr required = (15/12) × 6 = 7.5 Amp-Hr
For 20 W device,
Current, I = 20/12 Amp
Amp-Hr Required = (20/12) × 3 = 5 Amp-Hr
Therefore, the minimum Amp-Hr required is – 5+7.5 = 12.5 Amp-Hr
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Community Answer
A device consuming 15 W is switched on for 6 hours a day and another d...
Power Consumption Calculation
To find the minimum Ah rating of a 12 V battery that can support the devices, we need to calculate the total energy consumed by both devices in a day.
Device 1: 15 W for 6 hours
- Daily energy consumption = Power × Time
- Daily energy = 15 W × 6 h = 90 Wh
Device 2: 20 W for 3 hours
- Daily energy consumption = Power × Time
- Daily energy = 20 W × 3 h = 60 Wh
Total Energy Consumption
- Total daily energy = Energy from Device 1 + Energy from Device 2
- Total daily energy = 90 Wh + 60 Wh = 150 Wh
Battery Capacity in Ah
To convert watt-hours (Wh) to ampere-hours (Ah), we use the formula:
- Capacity (Ah) = Energy (Wh) / Voltage (V)
Given that the battery voltage is 12 V:
- Capacity = 150 Wh / 12 V = 12.5 Ah
Conclusion
The minimum Ah rating of the 12 V battery required to support both devices for their respective durations is 12.5 Ah. Hence, the correct answer is option 'A'.
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A device consuming 15 W is switched on for 6 hours a day and another device consuming 20 W is operated for 3 hours a day. The minimum Ah rating of a 12 V battery supplying power to the devices isa)12.5 Ahb)35 Ahc)15 Ahd)20 AhCorrect answer is option 'A'. Can you explain this answer?
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