A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer G attached across the coil?

Three positions shown describe: (a) the magnet's entry (b) magnet is completely inside and (c) magnet's exit.

$$\text{Position (a) [Entry]: Flux is increasing} \implies \varepsilon = -\frac{d\phi}{dt} \neq 0 \implies \text{Deflection in one direction (e.g., right)}$$

$$\text{Position (b) [Inside]: Flux is constant} \implies \frac{d\phi}{dt} = 0 \implies \varepsilon = 0 \implies \text{No deflection (centre)}$$

$$\text{Position (c) [Exit]: Flux is decreasing} \implies \frac{d\phi}{dt} \text{ changes sign} \implies \text{Deflection in the opposite direction (e.g., left)}$$

Comparing with the given choices: The sequence of galvanometer needles must show a rightward tilt, a central vertical alignment, and a leftward tilt.

Answer: Option (B): Needle deflects right at entry, stays at centre when inside, and deflects left at exit.