Voltage and Resistance Exercise, .

In summary, to determine the current and voltage in a series circuit with two resistors (R1=10 ohms, R2=30 ohms) and a potential difference of 12V, the total resistance (Req) is found by adding the individual resistances. Using the formula V=IR, the current (i) is calculated to be 0.3A. The voltage across each resistor is then determined by multiplying the resistance by the current (-3V for R1 and -9V for R2). It is possible for the voltage to be negative as it is a relative measurement. However, it is important to properly apply Kirchoff's Voltage Law and ensure that the sum of the voltages in the circuit
  • #1
claudiadeluca
9
0
Please help with the following exercise:

Given 2 resistors in series R1=10 ohms, R2= 30 ohms, determine the current flowing through the resistors and the voltage across each resistor, if the potential difference across the wire is V=12V.

This is how I solved it:

The total resistance Req= R1+R2= 40 ohms

R = V / i
i = V/R = 0.3 A

V(R1) = -R1*i = -10*0.3= -3V
V(R2) = -R2*i = -30*0.3= -9V

Is it correct? Can the voltage be negative? Please help.

Thank you.
 
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  • #2
Voltage can be negative because it is a relative measurement.

I don't think you did yours right though. Draw the circuit out, and sum the voltages. They should sum to zero because of energy conservation, or otherwise known as Kirchoff's Voltage Law.
 
  • #3


Your solution is correct. The voltage can be negative in this case because it represents the potential difference across the resistor, which can be either positive or negative depending on the direction of the current flow. In this case, the negative sign indicates that the voltage drop is in the opposite direction of the current flow.
 

What is voltage?

Voltage is the measure of electrical potential difference between two points in an electric circuit. It is measured in volts (V) and is responsible for the movement of electric charge.

What is resistance?

Resistance is the measure of how difficult it is for an electric current to flow through a material. It is measured in ohms (Ω) and is affected by factors such as material, length, and cross-sectional area.

How do voltage and resistance affect each other?

According to Ohm's Law, voltage and resistance are directly proportional. This means that as voltage increases, resistance also increases, and vice versa. This relationship can be represented by the equation V = IR, where V is voltage, I is current, and R is resistance.

What is the role of voltage and resistance in exercise?

In exercise, voltage and resistance are important factors in muscle contraction. When a muscle is activated, it creates an electrical signal that travels through neurons to the muscle fibers, causing them to contract. The amount of voltage and resistance determines the intensity and effectiveness of the muscle contraction.

What are some examples of voltage and resistance exercises?

Some examples of voltage and resistance exercises include weightlifting, resistance band exercises, and bodyweight exercises. These exercises involve using external resistance, such as weights or bands, to create tension and challenge the muscles, leading to adaptations and strength gains.

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