Question

What will happen if voltmeter is connected in series and an ammeter is connected in parallel (in two different circuits of course) ​

Answer 1

Voltmeter has a high resistance

Thus connecting in parallel would give wrong readings.

Voltmeter is connected in parallel to find the potential difference between two points in the circuit.

An ammeter has a very low internal resistance. So, if it is connected in parallel with a load, it will short-out that load in resulting a high current flowing through the ammeter may severely damage the ammeter (and possible harm the user), although most are fitted with fuses to protect them.

Answer 2

Ammeter:-

An ammeter is just a converted Galvanometer and measures the current flowing through the circuit by showing proportional deflection. An ammeter is formed by connecting a Galvanometer with a low resistance in parallel.

$\bigstar$So the Ammeter is connected in series with the circuit elements and measures the current flow in a circuit.

Voltmeter:-

A Voltmeter is also a converted Galvanometer which measures the amount of Voltage (or) in other words the potential difference accross two points in a circuit. A voltmeter is formed by connecting a Galvanometer in series with a high resistance.

$\bigstar$So the Voltmeter is attached in parallel in a circuit and measures the voltage in a circuit.

And if this is not maintained then there is a high chance for the ammeter to get damaged due to low resistance.