Question

In a circuit, current is:

A. increased by the presence of a resistor.
B. the movement of charge.
C. an accumulation of charge.
D. measured in ohms.

Answer 1

@lupita1995

Answer 2

If the two requirements of an electric circuit are met, then charge will flow through the external circuit. It is said that there is a current - a flow of charge. Using the word current in this context is to simply use it to say that something is happening in the wires - charge is moving. Yet current is a physical quantity that can be measured and expressed numerically. As a physical quantity, current is the rate at which charge flows past a point on a circuit. As depicted in the diagram below, the current in a circuit can be determined if the quantity of charge Q passing through a cross section of a wire in a time t can be measured. The current is simply the ratio of the quantity of charge and time.


Current is a rate quantity. There are several rate quantities in physics. For instance, velocity is a rate quantity - the rate at which an object changes its position. Mathematically, velocity is the position change per time ratio. Acceleration is a rate quantity - the rate at which an object changes its velocity. Mathematically, acceleration is the velocity change per time ratio. And power is a rate quantity - the rate at which work is done on an object. Mathematically, power is the work per time ratio. In every case of a rate quantity, the mathematical equation involves some quantity over time. Thus, current as a rate quantity would be expressed mathematically as


Note that the equation above uses the symbol I to represent the quantity current.

As is the usual case, when a quantity is introduced in The Physics Classroom, the standard metric unit used to express that quantity is introduced as well. The standard metric unit for current is the ampere. Ampere is often shortened to Amp and is abbreviated by the unit symbol A. A current of 1 ampere means that there is 1 coulomb of charge passing through a cross section of a wire every 1 second.

1 ampere = 1 coulomb / 1 second
To test your understanding, determine the current for the following two situations. Note that some extraneous information is given in each situation. Click the Check Answer button to see if you are correct.

A 2 mm long cross section of wire is isolated and 20 C of charge is determined to pass through it in 40 s.


A 1 mm long cross section of wire is isolated and 2 C of charge is determined to pass through it in 0.5 s.


I = _____ Ampere


I = _____ Ampere

Answer 3

B??

Answer 4

yes

Answer 5

thanks got a couple more