- #1
Miss_e101
- 4
- 0
Hello all!
I'm confused about an explanation that my textbook gives, and I'm wondering if someone can help me understand it. The passage is as follows:
A circuit consists of a 12 V battery with negligible internal resistance, in parallel with a charging unit with an emf of 15 V and internal resistance of 0.5 ohms. These two components provide power for all the car's electrical equipment.
The car's battery maintains an emf of 12 V across it, because of its negligible internal resistance. Hence, the terminal p.d. of the charging unit must also be 12 V. This implies that 3 V must be "lost volts" across the internal resistance of the charging unit. Since its internal resistance is 0.5 V, there must be a current of 6 A supplied by the charging unit.
I'm confused specifically with the underlined statement - why does the p.d. of the charging unit have to be 12 V as well? Is it because the battery is actually powering the charging unit? Why then does it have an emf of 15 V?
Any insight would be appreciated.
Miss E.
I'm confused about an explanation that my textbook gives, and I'm wondering if someone can help me understand it. The passage is as follows:
A circuit consists of a 12 V battery with negligible internal resistance, in parallel with a charging unit with an emf of 15 V and internal resistance of 0.5 ohms. These two components provide power for all the car's electrical equipment.
The car's battery maintains an emf of 12 V across it, because of its negligible internal resistance. Hence, the terminal p.d. of the charging unit must also be 12 V. This implies that 3 V must be "lost volts" across the internal resistance of the charging unit. Since its internal resistance is 0.5 V, there must be a current of 6 A supplied by the charging unit.
I'm confused specifically with the underlined statement - why does the p.d. of the charging unit have to be 12 V as well? Is it because the battery is actually powering the charging unit? Why then does it have an emf of 15 V?
Any insight would be appreciated.
Miss E.