Electric Current and Circuits

A 9.0-V battery is connected to a 3.5-Ω resistor and a 2.5-Ω resistor connected in series. Which statement is true?

• The total electric potential and the electric potential for each resistor is the same.

• The total current out of the battery and the current through each resistor is the same.

• The total current out of the battery gets split up among the resistors.

• Each resistor outputs the same power.

Answer explanation

Only one path for current to flow on in a series circuit means the amount of the current is the same throughout the circuit.

The current going through the 8.0-Ω resistor is ___ A.

Mathematical Equivalence

ON

Answer explanation

Series connections for the resistors means the total resistance is:

R_tot = 8.0 + 16.0 + 6.0

R_tot = 30.0 Ω

Ohm's Law is used to find total current:

12 = I·30.0

0.40 A = I

Match the following circuit elements to their symbols.

• battery

• 
• lamp

• 
• ammeter

• 
• switch

• 
• resistor

• 

Since there are multiple pathways the current can take from the positive side of the battery to the negative side, in a ​ (a)   circuit, the ​ (b)   is divided up among the pathways, but the potential is the same for each pathway. ​In ​ (c)   circuits with only one pathway for the current, the ​ (d)   is divided up among the different elements.

• parallel
• current
• series
• potential

Suppose light bulb and socket C was removed from the circuit shown. Wire is used to connect the switch to light bulb and socket B instead. What will happen to the total voltage of the battery when this happens?

• It will stay the same.

• It will increase so the bulbs A and B burn brighter.

• It will decrease so the bulbs A and B will dim.

• The circuit cannot work without light bulb and socket C where it is.

• Series combination

• Parallel combination

A potential difference of 24 V is applied to a 150-Ω resistor. How much current flows through the resistor?

• 0.15 A

• 3600 A

• 6.25 A

• 0.16 A

What will happen if one light bulb is removed from this circuit?

• The other bulbs will go out.
• The other bulbs will stay on
• The other bulbs will get dimmer.
• The battery will become stronger.

A 200-W light bulb is connected across a 100-V dc power supply. What current will flow through this bulb?

• 0.90 A

• 0.36 A

• 0.60 A

• 2.0 A

The current through the starter motor of a car is 210 A. If the battery maintains 12 V across the motor, how much electrical energy is delivered to the starter in 10.0 s?

• 2500 J

• 25200 J

• 17.5 J

• 175 J

Answer explanation

Electrical energy is PE (or W).

PE = P·t

To find P:

P = V·I

P = 12·210

P = 2520 W

PE = 2520·10

PE = 25200 J

Tags

NGSS.HS-PS3-1