help for physics paper 1 0625 ASAP plz

[Osmix1995]

i Can't understand the reason why the Answer is C

 

[IG4ever]

current flows from +ve to -ve........when he moves he contact k upwards ......current will flow in a smaller part in the resistor then to L2.....so L2 gains more current (voltage) so its brighter......eventually L1 becomes dimmer

 

[Sadiq]

current flows from +ve to -ve........when he moves he contact k upwards ......current will flow in a smaller part in the resistor then to L2.....so L2 gains more current (voltage) so its brighter......eventually L1 becomes dimmer

The best way to look at it as follows:

This is a potential divider, when you move K towards X, voltage across L1 decreases whereas the voltage across L2 increases. The power dissipated across the bulbs will be given by IV=V^2/R. So the bulb L1 will get dimmer as the voltage decreases and bulb L2 get brighter as the voltage increases. Note the resistances of the bulb do not change, as they are still the same bulbs!

 

[IGCSE O/L student]

the potential divider is made of a resistor wid a contact(wire). wen u move da contact towards X, da share of resistance L2 gets increases, so da voltage across it increases.thus it becums brighter. meanwhile, da share of resistance L1 gets decreases, so da voltage across it decreases, n so it becums dimmer.
i knw it's too late, but i hope it'll help u 4 paper 3 and 6. Gud luck!!!