# Higher Physics Help ? Electricity and circuits.Watch

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#1
Hey guys.

Any help with this question?

A source of EMF 6V and internal resistance 5Ω is connected in series with a 5.5Ω and a 3Ω resistor.

Find

a) The potential difference across the 5.5Ω and 3Ω resistors

b) The power dissipated in the 5.5Ω and the 3Ω resistors.

c) If a 3Ω resistor is placed in parallel with the existing 3Ω resistor, thencalculate the new current flowing in the circuit.
0
5 years ago
#2
(Original post by lilangel217)
Hey guys.

Any help with this question?

A source of EMF 6V and internal resistance 5Ω is connected in series with a 5.5Ω and a 3Ω resistor.

Find

a) The potential difference across the 5.5Ω resistors

b) The power dissipated in the 5.5Ω and the 3Ω resistors.

c) If a 3Ω resistor is placed in parallel with the existing 3Ω resistor, then calculate the new current flowing in the circuit.
For a) Remember that the potential difference can also be known as the volts. Using the equation Emf = I(R + r) you can calculate the current.
From there, as you know the resistance (5.5) you can use V = IR to solve it

For b) I'm guessing you're meant to use P=IV for each one, though you need to calculate the voltage across the 3 ohms.

For c) You'd have to work out the new total resistance, then use V=IR to calculate new current.

You could also post in the higher physics thread if you need any more help.
If this didn't make sense then feel free to ask more questions
0
#3
For a) Remember that the potential difference can also be known as the volts. Using the equation Emf = I(R + r) you can calculate the current.
From there, as you know the resistance (5.5) you can use V = IR to solve it

For b) I'm guessing you're meant to use P=IV for each one, though you need to calculate the voltage across the 3 ohms.

For c) You'd have to work out the new total resistance, then use V=IR to calculate new current.

You could also post in the higher physics thread if you need any more help.
If this didn't make sense then feel free to ask more questions
Thanks a bunch.

Just checked, and had to go back and change a) though, as it was for across both resistors. Does it change any calculations ?
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