# A level physics - help please

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#1
A sinusoidally-varying voltage that has a frequency of 1750 Hz, is applied across a 0.5 W, 24 Ω resistor.
What is the peak value of the voltage such that the resistor is not overloaded?
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8 months ago
#2
(Original post by Folayemi.f)
A sinusoidally-varying voltage that has a frequency of 1750 Hz, is applied across a 0.5 W, 24 Ω resistor.
What is the peak value of the voltage such that the resistor is not overloaded?
Frequency is irrelevant information for a resistive load - is that the complete question?

for calculating power dissipation with sinusoidal AC you need to use Volts RMS (or Amps RMS)
here is why https://www.bbc.co.uk/bitesize/guide...7ty/revision/4

and then convert V RMS to V peak
0
#3
(Original post by Joinedup)
Frequency is irrelevant information for a resistive load - is that the complete question?

for calculating power dissipation with sinusoidal AC you need to use Volts RMS (or Amps RMS)
here is why https://www.bbc.co.uk/bitesize/guide...7ty/revision/4

and then convert V RMS to V peak
Yes it’s the complete question, I don’t really understand either, and I have no idea how to start
0
8 months ago
#4
(Original post by Folayemi.f)
Yes it’s the complete question, I don’t really understand either, and I have no idea how to start
You could start with P=V2/R which would give you the RMS Volts - you can think of RMS Volts as being 'equivalent' to DC Volts in terms of delivering power into resistors, heaters and light bulbs.

Then convert RMS to peak as shown in the link - if you need help to remember whether you should be multiplying or dividing by the constant sqrt(2) you can remember that peak is always higher than RMS
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