Why does a galvanometer not show full-scale deflection after connecting it in a circuit?

$A$ galvanometer has $36\,\Omega$ resistance. If a $4\,\Omega$ shunt is added to this,the fraction of current that passes through the shunt is

$A$ galvanometer of resistance $G$ is shunted by a resistance of $5 \Omega$. To keep the main current in the circuit unchanged,the resistance to be put in series with the same galvanometer is

An ammeter of resistance $R$ gives a full-scale deflection when a current of $2 \ A$ passes through it. If it is to be converted into an ammeter to measure a maximum current of $10 \ A$,the required shunt is:

An ammeter reads up to $1\, A$. Its internal resistance is $0.81\, \Omega$. To increase the range to $10\, A$,the value of the required shunt is ............ $\Omega$.

The current sensitivity of a moving coil galvanometer is increased by $25 \%$. This increase is achieved only by changing the number of turns of the coils and the area of the cross-section of the wire while keeping the resistance of the galvanometer coil constant. The percentage change in the voltage sensitivity will be $...........\%$