Question

Which one of the following statements is correct?
A: An ammeter is connected in series in a circuit
B: A voltmeter is connected in series in a circuit
C: An ammeter has a high resistance
D: A voltmeter has a low resistance

Answer 1

Hint : An ammeter is a device which is used to measure the amount of electric current flowing through a conductor. Whereas a voltmeter is a device used to measure the amount of potential difference, also known as voltage, across two points in a conductor.

Complete solution:
An ammeter is an instrument that measures the difference in electrical potential between two points in an electric circuit. An analog voltmeter moves the pointer across scale in proportion to the circuit voltage and a digital voltmeter provides a numeric display. Any measurement that can be converted to voltage can be displayed on a meter that is properly calibrated. Search measurements include pressure temperature and flow.
Ammeter measure the electric current in a circuit, the name is derived from the name for SI unit for the electric current ampere (A)
In order for an ammeter to measure a device current it must be connected in series to the device, this is necessary because an object in series experiences the same current, it must not connect across a voltage source.
An ammeter is connected in series with the circuit because the purpose of the ammeter used to measure the current through the circuit. Since ammeter is a low impedance device, connecting it in parallel with the circuit would cause a short circuit damaging the ammeter, therefore it should be connected in series. So that maximum current can pass through it, for accurate measurement of current its resistance is very low. If it is connected in parallel across the circuit, it cannot measure the current accurately.

Option A is correct.

Note: The device, which measures the amount of current flowing in a circuit, it has a very low resistance (nearly zero resistance) device. If it is connected in parallel, it would draw most of the current and would get damaged and it is connected in series. The device, which measures the amount of potential difference across a resistor or a series of resistor. It is a very high resistance (nearly infinite resistance) device. If it will be connected in series, it would increase the equivalent resistance of the circuit.