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All the elements in the circuit shown in the following figure are ideal. Which of the following statements is/are true?

When switch
is
, both
and
conducts and
is reverse biased.
When switch
is
conducts and both
and
are reverse biased.
When switch
is OFF,
is reverse biased and both
and
conduct.
When switch
is OFF,
conducts,
is reverse biased and
conducts.
When S is ON, diode D3 gets reverse biased
Assume D1 is ON & D2 is OFF

I1 = 4A > 0 ∴D1 is ON
VD2 = -20 V < 0 ∴D2 is OFF
∴ Option (b) is correct
When S is OFF, D3 is ON due to 2A current source Assume D1 is OFF & D2 is ON

ID2 = 4A > 0 ∴ D2 is ON
VD1 = 20 – 40 = -20 < 0 ∴D1 is OFF
∴ Option (c) is correct