Circuits

Two resistors are connected to a source of voltage as shown in the diagram below. At which position should an ammeter be placed to measure the current passing only through resistor R1?

• 1
• 2
• 3
• 4

What must be inserted between points A and B to establish a steady electric current in the incomplete circuit represented in the diagram below?

• magnetic field source
• switch
• source of potential difference
• voltmeter

A 2.0-ohm resistor and a 4.0-ohm resistor are connected in series with a 12-volt battery. If the current through the 2.0-ohm resistor is 2.0 amperes, the current through the 4.0-ohm resistor is

• 1.0 A
• 2.0 A
• 3.0 A
• 4.0 A

Where should an ammeter be located to correctly measure the total current and where should a voltmeter be located to correctly measure the total voltage?

• ammeter at 3 and voltmeter at 4
• ammeter at 1 and voltmeter at 4 
• ammeter at 2 and voltmeter at 3 
• ammeter at 1 and voltmeter at 2

Resistors R1 and R2, connected in parallel, have an equivalent resistance of 6 ohms when connected in the circuit shown below. The resistance of R1 could be

• 1 ohm
• 4 ohms
• 5 ohms
• 8 ohms

A 30.-ohm resistor and a 60.-ohm resistor are connected in an electric circuit as shown below. Compared to the electric current through the 30.-ohm resistor, the electric current through the 60.- ohm resistor is

• smaller
• larger
• cannot be determined
• the same 

An electric circuit contains an operating heating element and a lit lamp. Which statement best explains why the lamp remains lit when the heating element is removed from the circuit? 

• The lamp has less resistance than the heating element.
• The lamp has more resistance than the heating element
• The lamp and heating element were connected in parallel.
• The lamp and heating element were connected in series.

 A circuit consists of a resistor and a battery. Increasing the voltage of the battery while keeping the temperature of the circuit constant would result in an increase in

• current only
• resistance only
• both current and resistance
• neither resistance nor current

The current through a 10.-ohm resistor is 1.2 amperes. What is the potential difference across the resistor?

• 14V
• 12V
• 120V
• 8.3V

A 9.0-volt battery is connected to a 4.0-ohm resistor and a 5.0-ohm resistor as shown in the diagram below. What is the total resistance

• 4 ohms
• 5 ohms
• 1 ohms
• 9 ohms