The hot wire ammeter A in Fig. shows some deflection, but not in Fig. Why ?

Hot wire ammeters can measure :

In a hot wire ammeter the deflection angle theta of the pointer is related with the current I as

A potentiometer wire AB having length L and resistance 12 r is joined to a cell D of emf epsi//2 and internal resistance 3r is connected. The length AJ at which the galvanometer as shown in fig. Shows no deflection is :

A potentiometer wire AB having length L and resistance 12 r is joined to a cell D of emf epsi//2 and internal resistance 3r is connected. The length AJ at which the galvanometer as shown in fig. Shows no deflection is :

A voltmeter, an ammeter and a resistance are connected in series with a lead accumulator. The voltmeter gives some deflection but the deflection of ammeter is almost zero. Explain why?

When primary coil P is moved towards secondary coil S (as shown in the Fig.) the galvanometer shows momentary deflection. What can be done to have larger deflection in the galvanometer with the same battery?