AC and DC both can be measured by ?

Hint:An isolated conductor, like wire, contains a few electrons moving at random with high speeds. These are called conduction electrons. The rate at which these electrons pass from left to right through an area in a wire is the same as the rate at which they pass from right to left through the same area, the rate is zero. The current is defined as the rate at which charge flows through the given area in unit time.

Complete answer:
 We often study two types of currents namely, AC i.e. alternating current and DC i.e., direct current.
Direct current (DC):- Direct current is directional flow of electric current . In simple terms it is unidirectional current. Direct current may flow through a conductor such as wire, but also through semiconductor , insulator. Direct current can increase or decrease in all sorts of ways, but the magnitude remains the same. Large quantity of current flows through direct current . Direct current has many uses such as in electrochemical cells, smelting of aluminium , charging of batteries etc.

Alternating current (AC):- Most of the power generated and used in the world is in the form of alternating current. An alternating current is the current is the current whose value changes with time in both magnitude and direction. Alternating current varies sinusoidally. The frequency of alternating current is 50Hz. Alternating current has many uses such as the current supply in our home is alternating current, to change voltage from low to high and back from high to low, in transformers etc.

AC and DC both can be measured by Hotwire instruments that use the heating effect of current for measuring magnitude. The length of hot wire increases with the passage of current . Hotwire construction is simple and cheap. It is not affected by the magnetic field.

Note:The Hotwire instrument consumed more power and it’s response time is slow.The instrument cannot cooperate with overload or mechanical shock.Unlike alternating current, the flow of direct current does not change periodically. The current electricity flows in a single direction in a steady voltage. The major use of DC is to supply power for electrical devices and also to charge batteries.