# CircuitsWatch

#1
Why is the answer C? I thought it would be E as 6/6 = 1A for switch open and 6/2=2A for switched closed.
0
4 years ago
#2
(Original post by Peanut247)
Why is the answer C? I thought it would be E as 6/6 = 1A for switch open and 6/2=2A for switched closed.

Why do you divide by 2 for the switch closed case?
Where does 2 ohm come from? (Edit: I think you meant 6/3.)
Note that the diode is reverse biased.
#3
(Original post by Stonebridge)
Why do you divide by 2 for the switch closed case?
Where does 2 ohm come from?
Note that the diode is reverse biased.

Who says the answer is C, by the way.
Sorry I meant 6/3=2A

The mark scheme says the answer is EDIT: the answer is B - but I can't figure out why.
Why is the diode significant when the switch it closed because shouldn't all the current flow through the alternative branch now?
Reverse biased?
0
4 years ago
#4
(Original post by Peanut247)
Sorry I meant 6/3=2A

The mark scheme says the answer is C but I can't figure out why.
Why is the diode significant when the switch it closed because shouldn't all the current flow through the alternative branch now?
Reverse biased?

C is not correct.
With the switch open current cannot flow at all.
It can't flow through the switch branch and it can't flow in the reverse direction through the diode.
With the switch closed current just flows through the 3 ohm on the right and round the "short circuit" through the switch which has no resistance. I = 6/3 A
Current is clockwise.
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