Can anyone help me about Current ?

Question

is this correct.

The instrument used to measure current is an ammeter, it is connected in series.

Current in a series circuit is the same everywhere (only one track)

When more resistors (eg lamps) are connected in series, the more currents there is

and

is the componet that can be used to alter the current called a rheostat ?

If not could you please correct.

Also could you help me with the following...

fill in the gaps

The current in a parallel circuit ______ ____ in the branches to equal the current in the "main trunk". (electrons take their own route)

When more resistors (eg lamps) are connected in parallel, the ______ current there is. (Think 4 plugs.....)

Answer 1

Q1.    Is correct, the instrument used to measure current is an Ammeter there are 2 basic types in common use. The series connected moving coil instrument and the "Clip on" type ammeter. The clip on measures the strength of the magnetic field produced in a conductor when current flows though it, the internal circuitry then converts this into Amperes for the digital readout.

Q2.   Is Correct, in series circuits the current is equal throughout.

Q3.   Is not correct when more resistors are connected in series the current decreases. Imagine a hosepipe with water flowing out of the end. Using one hand squeeze the pipe to introduce the first resistance. The water flow will decrease. Now further along the pipe use your second hand to introduce a second resistance squeezing the pipe also. The water flow decreases further and so on. As more resistance is introduced in series the flow (electric current ) decreases.

Q4. A rheostat is a variable resistor and can be likened to a water tap (fawcett) As you turn the tap clockwise/counter clockwise the water flow is altered. Similarly with a rheostat as it is moved it resistance changes and hence the electric current changes.

Q5.  The current in a parallel circuit SHOULD ADD in the branches to equal the current in the main trunk.

This would be better written "the current in the branches of a parallel circuit, when algebraically added should equal the current in the main trunk".

Q6.  When more resistors are connected in parallel. the MORE current there is.

Imagine 100 passengers exit a train and only one exit gate is open the flow is one person at a time. If 5 exit gates were opened (In parallel) the flow would increase to 5 persons per time    

  

Answer 2

When more resistors (eg lamps) are connected in series, the more currents there is -> nope, more resistors will mean that that current is reduced.

A reostat alter the resistance, it is a variable resistor, which interns will have an effect on the current flowing through it.

The current in a parallel circuit ______ ____ in the branches to equal the current in the "main trunk". (electrons take their own route) -> is devided

When more resistors (eg lamps) are connected in parallel, the ______ current there is. (Think 4 plugs.....) more

Answer 3

The instrument used to measure current is an ammeter, it is connected in series.

This is correct because the current must pass through the meter.

Current in a series circuit is the same everywhere (only one track)

Correct. Just as voltage is the same everywhere in a parallel circuit.

When more resistors (eg lamps) are connected in series, the more currents there is.

This is not correct because as resistance goes up, currect goes down. For example, if you have two 2-ohm lamps and a 12 V source in series, then the current is 12V/2-ohms = 6 amps. Increase the number of series lamps by one and you have 12V/3-ohms = 4 amps. The anser should read "the less current there is."

is the componet that can be used to alter the current called a rheostat ?

Yes. A rheostat is also called a variable resistor. If you change the resistance in a circuit, you change the current (by Ohm's law).

Fill in the blank:

1. You might say "is divided."

2. More. (This is true because the total resistance decreases with more branches.)