State $Ohm's$ law. How can it be verified ?
State $Ohm's$ law. How can it be verified ?
It states "Physical conditions' remaining same, the current flowing through a conductor is directly proportional to the potential difference across its two ends".
i.e., $V \propto I$
Or $V = IR$
where the constant of proportionality $R$ is called the electrical resistance or resistance of the conductor.
Verification: The following circuit diagram is used to verify Ohm's law.
Take a few cells; connect one cell across a nichrome wire $AB$, along with an ammeter and a voltmeter as shown in figure. Note the voltage and the current from the voltmeter and the ammeter. Now, connect two cells and again note the voltage and the current. Repeat the procedure for three cells and four cells. Calculate the ratio for each set. You will find the ratio is the nearly same in all the cases. If a graph of current against voltage in plotted, it will turn to be a straight line as shown in figure. This shows that the current is directly proportional to the potential difference.
Similar Questions
$(a)$ In the circuit shown connect a nichrome wire of length ${ }^{\prime \prime} L^{\prime \prime}$ between points $X$ and $Y$ and note the ammeter reading.
$(i)$ When this experiment is repeated by inserting another nichrome wire of the same thickness but twice the length $(2 L),$ what changes are observed in the ammeter reading ?
$(ii)$ State the changes that are observed in the ammeter reading if we double the area of cross-section without changing the length in the above experiment. Justify your answer in both the cases.
$(b)$ "Potential difference between points $A$ and $B$ in an electric field is $1\, V^{\prime \prime} .$ Explain the statement.
$(a)$ In the circuit shown connect a nichrome wire of length ${ }^{\prime \prime} L^{\prime \prime}$ between points $X$ and $Y$ and note the ammeter reading.
$(i)$ When this experiment is repeated by inserting another nichrome wire of the same thickness but twice the length $(2 L),$ what changes are observed in the ammeter reading ?
$(ii)$ State the changes that are observed in the ammeter reading if we double the area of cross-section without changing the length in the above experiment. Justify your answer in both the cases.
$(b)$ "Potential difference between points $A$ and $B$ in an electric field is $1\, V^{\prime \prime} .$ Explain the statement.
$(a)$ What are the values of $mA$ and $\mu A$ ?
$(b)$ Draw the symbols of battery and rheostat.
$(a)$ What are the values of $mA$ and $\mu A$ ?
$(b)$ Draw the symbols of battery and rheostat.
What is meant by an electric circuit ? Draw a circuit diagram to show an electric circuit comprising of a battery of two cells, a resistor, an ammeter and plug key when cirfuit is closed.
What is meant by an electric circuit ? Draw a circuit diagram to show an electric circuit comprising of a battery of two cells, a resistor, an ammeter and plug key when cirfuit is closed.
The unit of measurement of charge is coulomb.
The unit of measurement of charge is coulomb.
Which of the following represents Ohm's law?
Which of the following represents Ohm's law?