(N/A) To obtain a large deflection,one or more of the following steps can be taken:
$(i)$ Use a rod made of soft iron inside the coil $C_2$.
$(ii)$ Connect the coil to a more powerful battery.
$(iii)$ Move the arrangement more rapidly towards or away from the test coil $C_1$.
$(b)$ Replace the galvanometer with a small bulb,such as one found in a small torch light. The relative motion between the two coils will cause the bulb to glow,thereby demonstrating the presence of an induced current.
In experimental physics,one must learn to innovate. Michael Faraday,who is ranked as one of the best experimentalists ever,was legendary for his innovative skills.