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# Quick question on circuits watch

1. Doing NSAA tomorrow so doing BMAT section 2 for practice, all question so far if I've gotten them wrong I can understand why but not with this one.
My initial answer was E, correct answer is B. I don't think circuits are even a part of the NSAA but I'd like to see the correct thinking for this.
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2. (Original post by JN17)
Doing NSAA tomorrow so doing BMAT section 2 for practice, all question so far if I've gotten them wrong I can understand why but not with this one.
My initial answer was E, correct answer is B. I don't think circuits are even a part of the NSAA but I'd like to see the correct thinking for this.
So with the switch open as you can see from the diagram the diode is positioned in the opposite direction to current flow hence will lead to no current flowing through the amp meter (flowing from positive to negative). However with the switch close the current swill won't flow through the left resistor due to the diode still being there however a circuit will have been completed with just the left hand side 3 OHM resistor bypassing the diode, hence the current will be 6/3 = 2A (V=I.R)

Hope that makes some sense, good luck for tomorrow!
3. So for these questions do you follow conventional current then? I thought of it as negative to positive in which case the diode would be fine
4. (Original post by JN17)
So for these questions do you follow conventional current then? I thought of it as negative to positive in which case the diode would be fine
Yeah I always struggled to get over the fact that it seemed backwards, but its a somewhat definition for the drawing of diodes I guess, that the arrow of the diode for current to flow must be in the direction of conventional current.

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