JEE Advanced
Physics
Current Electricity
2022
JEE Advanced 2022 (Paper 2)
JEE Advanced Physics Question (2022) — Solution
Question
In Circuit- 1 and Circuit- 2 shown in the figures, R 1 = 1 Ω , R 2 = 2 Ω and R 3 = 3 Ω . P 1 and P 2 are the power dissipations in Circuit- 1 and Circuit- 2 when the switches S 1 and S 2 are in open conditions, respectively. Q 1 and Q 2 are the power dissipations in Circuit- 1 and Circuit- 2 when the switches S 1 and S 2 are in closed conditions, respectively. Which of the following statement(s) is(are) correct?
Options
- A. When a voltage source of 6 V is connected across A and B in both circuits, P 1 < P 2
- B. When a constant current source of 2 Amp is connected across A and B in both circuits, P 1 > P 2
- C. When a voltage source 6 V is connected across A and B in Circuit- 1 , Q 1 > P 1
- D. When a constant current source of 2 Amp is connected across A and B in both circuits, Q 2 < Q 1
Answer
C. When a voltage source 6 V is connected across A and B in Circuit- 1 , Q 1 > P 1
Step-by-step solution
When S 1 and S 2 are open For circuit 1 R eq 1 = 1 + 5 × 1 2 5 + 1 2 = 1 + 5 11 = 16 11   Ω P 1 = V 2 R eq = 6 2 16 × 11 = 36 × 11 16 = 24 . 75   W For circuit 2 R eq 2 = 6 11   Ω P 2 = V 2 R eq = 6 2 6 × 11 = 36 × 11 6 = 66   W Therefore, P 2 > P 1 Option A is correct ⇒ If 2 A source is used in both cases. P 1 = i 2 R eq   1 = 2 2 × 16 11 = 64 11 = 5 . 818   W P 2 = i 2 R eq 2 = ( 2 ) 2 × 6 11 = 24 11 = 2 . 1818   W P 1 > P 2 Option B is correct. When S 1 and S 2 are closed For Q 1 R eq = 5 11 Ω Q 1 = V 2 R eq = 6 2 5 11 = 36 × 11 5 = 79 . 2   W P 1 = 24 . 75   W Therefore, Q 1 > P 1 Option C is correct. For option D Q 1 = i 2 R eq = 2 2 × 5 11 = 20 11 = 1 . 81   W Q 2 = i 2 R eq = 2 2 × 1 2 = 4 2 = 2   W Q 2 > Q 1 Option D is incorrect.
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