confused (1 Viewer)

[kkk579]

can someone pls explain the working out for this q??? thank you!
i am confused because r3 and r4 r in series right? so it makes sense that their voltages r different but why r their currents different? and same goes for r1 and r2

 

[kkk579]

also for this q arent they finding the intensity not the power in part a in their given working out?

 

[wollongong warrior]

can someone pls explain the working out for this q??? thank you!View attachment 44057
i am confused because r3 and r4 r in series right? so it makes sense that their voltages r different but why r their currents different? and same goes for r1 and r2

r3 and r4 are not in series. See that there's a wire between them. If they were placed along a single, unintercepted wire then they'd be in series
And just a bit more, because there's a wire between them, this means that the voltages of r2 and r4 are equal so find that voltage, use V = IR to find the currents flowing through r2 and r4

 

[kkk579]

how do u know that the voltage pf r2 and r4 r equal

r3 and r4 are not in series. See that there's a wire between them. If they were placed along a single, unintercepted wire then they'd be in series
And just a bit more, because there's a wire between them, this means that the voltages of r2 and r4 are equal so find that voltage, use V = IR to find the currents flowing through r2 and r4

 

[wollongong warrior]

how do u know that the voltage pf r2 and r4 r equal

Voltage is a differential quantity. You can think of r2 and r4 being connected to the same 2 points.

So obviously, they'll have the same voltage and it's the reason why a voltmeter is connected in parallel to a component because it's measuring what the difference in voltage is between its 2 endpoints (I didn't notice the voltmeter in your question when I answered it last night lol)

 

[kkk579]

Okay yeah it makes sense that r2 and r4 r parallel

Voltage is a differential quantity. You can think of r2 and r4 being connected to the same 2 points.
View attachment 44065
So obviously, they'll have the same voltage and it's the reason why a voltmeter is connected in parallel to a component because it's measuring what the difference in voltage is between its 2 endpoints (I didn't notice the voltmeter in your question when I answered it last night lol)

and r1 and r3 r parallel but what r r3 and r4 in and same goes for r1 and r2?

 

[wollongong warrior]

Okay yeah it makes sense that r2 and r4 r parallel

and r1 and r3 r parallel but what r r3 and r4 in and same goes for r1 and r2?

They are neither parallel nor in series but you can say that the equivalent resistance of r1 and r3 is in series with the equivalent resistance of r2 and r4

 

[kkk579]

They are neither parallel nor in series

Oh so should we look at r1 and r3 as one loop and r2 and r4 as another when solving for the variables? because they have that wire in the middle

 

[kkk579]

so i should essentially be imagining the circuit like this:



sorry for the qs lol i think its cos of how they drew the circuit i interpreted it differently thats why im confused

also do u mind answering the other q i had abt the power and intensity?

 

[wollongong warrior]

Oh so should we look at r1 and r3 as one loop and r2 and r4 as another when solving for the variables? because they have that wire in the middle

You're overcomplicating it.
Combine r1 and r3, combine r2 and r4
We now see that the entire circuit is just one loop which has a current of 120mA
Express all the resistors as one resistor with a current of 120mA
Since we know the circuit's current and total resistance, we can calculate Vs
Since we know that the voltage between r2 and r4 is 36V, since voltage is a differential quantity and assuming that the circuit is grounded at the negative terminal of the voltage source, we see that the voltages of r1 and r3 is Vs - 36

 

[wollongong warrior]

so i should essentially be imagining the circuit like this:



sorry for the qs lol i think its cos of how they drew the circuit i interpreted it differently thats why im confused View attachment 44066

also do u mind answering the other q i had abt the power and intensity?

Yes that's correct

 

[kkk579]

You're overcomplicating it.
Combine r1 and r3, combine r2 and r4
We now see that the entire circuit is just one loop which has a current of 120mA
Express all the resistors as one resistor with a current of 120mA
Since we know the circuit's current and total resistance, we can calculate Vs
Since we know that the voltage between r2 and r4 is 36V, since voltage is a differential quantity and assuming that the circuit is grounded at the negative terminal of the voltage source, we see that the voltages of r1 and r3 is Vs - 36

Okay yeah this makes sense thank you!

 

[kkk579]

bump

 

[wizzkids]

Question 26(a) is examining Year 11 Physics content, namely the inverse square law of radiation intensity.
Intensity is measured in units of watts per square metre per steradian (solid angle). If the number of square metres of the solar panel is constant, then power is proportional to intensity.
The peak power on Earth compared to the peak power on Mars with be inversely proportional to the square of (the distance to Earth divided by the distance to Mars).
Question 26(b) is examining the formula for power in an electrical circuit P =V.I