A potentiometer is used to compare two EMFs. If the known EMF is 6V and the leng
Practice Questions
Q1
A potentiometer is used to compare two EMFs. If the known EMF is 6V and the length of the wire is 120 cm, what is the potential gradient if the length of the wire is used to balance an unknown EMF of 4V?
0.05 V/cm
0.03 V/cm
0.04 V/cm
0.02 V/cm
Questions & Step-by-Step Solutions
A potentiometer is used to compare two EMFs. If the known EMF is 6V and the length of the wire is 120 cm, what is the potential gradient if the length of the wire is used to balance an unknown EMF of 4V?
Correct Answer: 80 cm
Step 1: Identify the known EMF, which is 6V.
Step 2: Identify the length of the wire used for the known EMF, which is 120 cm.
Step 3: Calculate the potential gradient using the formula: Potential Gradient = Known EMF / Length of Wire.
Step 4: Substitute the values into the formula: Potential Gradient = 6V / 120 cm.
Step 5: Perform the division: 6V / 120 cm = 0.05 V/cm.
Step 6: Identify the unknown EMF, which is 4V.
Step 7: Use the potential gradient to find the length of wire needed to balance the unknown EMF using the formula: Length = Unknown EMF / Potential Gradient.
Step 8: Substitute the values into the formula: Length = 4V / 0.05 V/cm.
Step 9: Perform the division: 4V / 0.05 V/cm = 80 cm.
Potential Gradient – The potential gradient is the voltage per unit length of the wire, indicating how much voltage is present over a specific distance.
Potentiometer Principle – A potentiometer is used to measure unknown voltages by balancing them against a known voltage.
Proportional Relationships – Understanding the relationship between voltage and length in a potentiometer setup.
