Use the information in the table about four different electric circuits to answer the question.
Circuit Resistance (ohms) Voltage (V)
1 0.5 20
2 0.5 40
3 0.25 40
4 0.25 60
Which circuit will have the greatest electric current?
Responses
A) circuit 1
B) circuit 4
C) circuit 3
D) circuit 2
To determine which circuit will have the greatest electric current, we need to use Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R).
For circuit 1: I = 20V / 0.5Ω = 40A
For circuit 2: I = 40V / 0.5Ω = 80A
For circuit 3: I = 40V / 0.25Ω = 160A
For circuit 4: I = 60V / 0.25Ω = 240A
From the calculations, we can see that circuit 4 will have the greatest electric current. Therefore, the correct answer is:
D) circuit 4
Circuit A has a resistance of 7.5 ohms, and circuit B has a resistance of 5 ohms. Which statement about the circuits must be correct?
A) If the current in circuit A is equal to the current in circuit B, then the voltage in circuit A is less than the voltage in circuit B.
B) If the current in circuit A is less than the current in circuit B, then the voltage in circuit A is less than the voltage in circuit B.
C) If the voltage of circuit A is equal to the voltage of circuit B, then the current in circuit A is less than the current in circuit B.
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D) If the voltage of circuit A is equal to the voltage of circuit B, then the current in circuit A is equal to the current in circuit B.
To determine which statement about the circuits must be correct, we can use Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R).
For circuit A: I = V_A / 7.5Ω
For circuit B: I = V_B / 5Ω
From these equations, we cannot determine the relationship between the currents in the circuits based solely on the given resistances. Therefore, we can eliminate options A and C.
However, we can determine that if the resistance in circuit A is greater than the resistance in circuit B, and the current is the same in both circuits, then the voltage in circuit A must be greater than the voltage in circuit B. This is because for the same current, a higher resistance will require a higher voltage to overcome it. Therefore, the correct statement is:
A) If the current in circuit A is equal to the current in circuit B, then the voltage in circuit A is less than the voltage in circuit B.
Which statement best defines the resistance of an electric circuit?
A) It limits the amount of electrical energy that can pass through a circuit.
B) It is the measurement of the rate of electrical energy in a circuit.
C) It describes how much electrical energy passes in a circuit.
D) It is the amount of electrical energy that is available in a circuit.
The resistance of an electric circuit is best defined by:
A) It limits the amount of electrical energy that can pass through a circuit.
Resistance refers to the opposition to the flow of electrical current in a circuit. It is responsible for limiting the amount of current that can flow through a circuit by absorbing and transforming electrical energy into other forms such as heat or light. Therefore, option A accurately describes the role of resistance in an electric circuit.
An electric circuit has an expected current of 80 amps. An electrician measures the current in the circuit at 120 amps. Which statement provides a possible explanation for this observation?
A) The circuit has an extra resistor.
B) There is not enough voltage in the circuit.
C) A resistor in the circuit is broken.
D) There is not enough electrical energy in the circuit.
The correct explanation for the observation that the measured current in the circuit is higher than the expected current of 80 amps would be:
C) A resistor in the circuit is broken.
If a resistor in the circuit is broken, it would no longer provide the expected amount of resistance, allowing more current to flow through the circuit. This would result in a higher measured current than what was initially expected.