Find out the following in the electric circuit given in the figure-

(a) Effective resistance of two 8 ohm resistors in the combination.

(b) Current flowing through the 4-ohm resistor

Study the circuit and find out-

(a) Current in 12 ohm resistor

(b) Difference in the readings of ammeter A₁ and A₂ if any

A copper wire has a length L = 2 m, a cross-sectional area A = 0.5 mm², and resistivity ρ = 1.7 × 10^-8 Ωm. Calculate the resistance of another wire made of the same material whose length is twice the length of the wire but has the same cross-sectional area.

The below image shows a corrective measure for a particular defect of vision.

(a) Identify the defect of vision and state what kind of lens is used to correct this deficiency.

(b) Draw and label a ray diagram that shows the defect of vision in the above case before correction.