In the circuit given below, identify the lamp (L₁, L₂, L₃ and L₄) whose failure would not interrupt the power supply to the other lamps.

1. L₁
2. L₂
3. L₃
4. L₄

Equal volumes of water are added to three cylindrical jars A, B and C of same height and radii r_A, r_B and r_C respectively with r_B < r_A < r_C. If you blow air into the mouth of these jars, which tube will produce the shrillest note?

1. A
2. B
3. C
4. All will produce the notes of same shrillness

The correct formula to calculate the equivalent resistance of two resistors R₁ and R₂ when connected in parallel, is:

1. $\dfrac{\text R$1 + \text R2}{\text R1\text R2} \\[1em]
2. $\dfrac{\text R$1\text R2}{\text R1 + \text R2} \\[1em]
3. $\dfrac{\text R$1 - \text R2}{\text R1\text R2} \\[1em]
4. $\dfrac{\text R$1\text R2}{\text R1 - \text R2} \\[1em]

The diagram below shows the top view of the Wire A shown by a cross (X), carrying current into the plane of the paper. Which of the compasses is correctly aligned with the magnetic field produced by the current carrying wire?

1. Only 1 is aligned
2. Only 2 is aligned
3. Both 1 and 2 are aligned
4. Both 1 and 2 are not aligned