Here are the solutions to the problems:
Problem 1:
Calculate the potential difference across a 10 Ω resistor carrying current of 2 A.
Step 1: Identify the given values.
Resistance R=10Ω
Current I=2 A
Step 2: Use Ohm's Law to calculate the potential difference V.
The formula for Ohm's Law is V=IR.
V=(2A)×(10Ω)
V=20 V
PotentialdifferenceV=20V
Problem 2:
The potential difference across a 3 Ω resistor is 12 V. What is the current flowing?
Step 1: Identify the given values.
Resistance R=3Ω
Potential difference V=12 V
Step 2: Use Ohm's Law to calculate the current I.
Rearranging Ohm's Law V=IR for I:
I=RV
I=3Ω12V
I=4 A
CurrentI=4A
Problem 3:
Find the potential difference across a conductor of resistance 2 Ω if the charge of 180 C flows for 2 minutes.
Step 1: Identify the given values and convert units.
Resistance R=2Ω
Charge Q=180 C
Time t=2minutes=2×60s=120 s
Step 2: Calculate the current I using the formula I=tQ.
I=120s180C
I=1.5 A
Step 3: Use Ohm's Law to calculate the potential difference V.
The formula for Ohm's Law is V=IR.
V=(1.5A)×(2Ω)
V=3 V
PotentialdifferenceV=3V
Problem 4:
A current of 4 A flows through an electric kettle. The p.d. across it is 8 V. Find the resistance.
Step 1: Identify the given values.
Current I=4 A
Potential difference V=8 V
Step 2: Use Ohm's Law to calculate the resistance R.
Rearranging Ohm's Law V=IR for R:
R=IV
R=4A8V
R=2Ω
ResistanceR=2Ω
Problem 5:
The potential difference across a 2 kΩ resistor is 4 V. Determine the current flowing in the circuit.
Step 1: Identify the given values and convert units.
Resistance R=2kΩ=2×103Ω=2000Ω
Potential difference V=4 V
Step 2: Use Ohm's Law to calculate the current I.
Rearranging Ohm's Law V=IR for I:
I=RV
I=2000Ω4V
I=0.002 A
This can also be expressed in milliamperes:
I=2×10−3A=2 mA
CurrentI=0.002A(or2mA)