How do you calculate the resistance of a lamp?
Calculating resistance
- To find the resistance of a component, you need to measure:
- The resistance is the ratio of potential difference to current.
- For example, 3 A flows through a 240 V lamp.
- resistance = 240 ÷ 3 = 80 Ω
- If you plot a graph of current against potential difference for a wire, you get a straight line.
How do you calculate amps from resistance?
Ohms Law and Power
- To find the Voltage, ( V ) [ V = I x R ] V (volts) = I (amps) x R (Ω)
- To find the Current, ( I ) [ I = V ÷ R ] I (amps) = V (volts) ÷ R (Ω)
- To find the Resistance, ( R ) [ R = V ÷ I ] R (Ω) = V (volts) ÷ I (amps)
- To find the Power (P) [ P = V x I ] P (watts) = V (volts) x I (amps)
What is the current through a resistor of resistance 2 ohms when connected to a 6v battery?
Explanation: So answer is 6/2= 3 amperes.
How do you find the resistance of an appliance?
Calculate the resistance, in Ohms, by dividing the voltage by the current. Ohms law states that voltage = current x resistance, so by rearranging the formula resistance = voltage / current. Using the example in Step 1, with a voltage of 50 volts and a current of 2 amps, the resistance is 50 / 2, or 25 ohms.
How do you find the value of the resistance?
Add all of the resistances across the circuit together to calculate the total resistance. If you don’t know the individual values, use the Ohm’s Law equation, where resistance = voltage divided by current. Plug in the values for voltage and current and solve for R to get the total resistance in a circuit.
Is there any change in current as it passes through a resistor?
And for a particular resistance, current depends on applied voltage. So, when current passes through a resistor, no change in current seen unless we change the resistance. Answer: No change in current.
Does the current change as it passes through a resistor Why or why not?
The current after a resistor is the exact same as it was before the resistor. If you now add a resistor in series into this circuit – the current of the circuit will be smaller. So yes, the resistor does reduce the current. (But the current flowing into the resistor is still the same as the current flowing out.)
Does current decrease with resistance?
If the resistance of R is increased the current in the circuit decreases, and vice versa. But for a given resistance the current is constant over the whole loop. When you have a higher resistance you have lower current .
What will happen to the resistance if the number of series devices increases?
As the number of resistors in a series circuit increases, the overall resistance increases and the current in the circuit decreases.
What happens to current when resistance is increased?
The relationship between resistance and the area of the cross section of a wire is inversely proportional . When resistance is increased in a circuit , for example by adding more electrical components , the current decreases as a result.
What happens to the current as the resistance increase?
Ohm’s law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Similarly, increasing the resistance of the circuit will lower the current flow if the voltage is not changed.
How will the resistance of a conductor change if it is stretched so that its length is doubled?
Complete step-by-step answer: (d) Resistivity of wire remains constant. As the length of wire gets doubled, the cross-sectional area will become half of its previous value because volume of wire remains constant. Hence, we can see that the new resistance is four times the previous resistance.
What will be the change in frequency of wire if its length is doubled?
From the above equation, we can infer that, the frequency of sound can remain unchanged even if we double the length of the wire, provided the tension of the wire is halved.
When the length of a wire is doubled then its resistance also gets doubled?
Complete answer: So, the new resistance, after doubling the length of the wire, becomes twice of the original resistance. Hence, if the length of a wire is doubled, then its resistance becomes doubled.
When the length and area of cross section both are doubled then the resistance will be?
Complete step by step answer: Thus, the above equation shows that the length of the conductor and the cross-section of the conductor are doubled, then the resistance of the conductor will remain the same, there is no change in the resistance of the conductor.
What happens to the resistance of a conductor when temperature is increased?
With increasing temperature, the resistance of the wire increases as collisions within the wire increase and “slow” the flow of current. Since conductors typically display an increased resistivity with temperature increase, they have a positive temperature coefficient.
What is the relation between temperature and resistance?
As temperature rises, the number of phonons increases and with it the likelihood that the electrons and phonons will collide. Thus when temperature goes up, resistance goes up. For some materials, resistivity is a linear function of temperature. The resistivity of a conductor increases with temperature.
How is the resistance of a metallic conductor affected by variation in temperature?
When the temperature of metallic conductor increases, the velocity of free electrons increases but it also cause increase in amplitude of vibration of metallic atoms which cause some extra resistance in the path of free electron. Hence resistance increases with increase in the temperature.