State with the help of a circuit diagram an activity to find the resistance ${ }^{\prime} R^{\prime}$ of a given wire. A current of $0.2\, A$ passes through a resistor of $20 \Omega$. Find the potential difference across its ends.
State with the help of a circuit diagram an activity to find the resistance ${ }^{\prime} R^{\prime}$ of a given wire. A current of $0.2\, A$ passes through a resistor of $20 \Omega$. Find the potential difference across its ends.
The circuit diagram is as shown
A circuit is set-up using the wire of resistor of value ${ }^{\prime} R ^{\prime}$, an ammeter, a voltmeter and four cells of $1.5 V$ each.
First one cell is used as source and the reading of ammeter and voltmeter is noted down to find the current $(I)$ and potential difference $(V)$.
The number of cells is increased one by one and the readings are noted down.
The average ratio of $V$ to $I$ gives the resistance $R ^{\prime}$ of the wire.
Given $I=0.15\,A,$ potential difference $=1.05 V$,
$=R=?$
$R=\frac{V}{I}=\frac{1.05}{0.15}=7$ ohm
Similar Questions
Two electric circuits $I$ and $II$ are shown in figure
$(i)$ Which of the two circuits has more resistance ?
$(ii)$ Through which circuit, more current passes ?
$(iii)$ In which circuit, the potential difference across each resistor is equal.
Two electric circuits $I$ and $II$ are shown in figure
$(i)$ Which of the two circuits has more resistance ?
$(ii)$ Through which circuit, more current passes ?
$(iii)$ In which circuit, the potential difference across each resistor is equal.
A large number of free electrons are present in metals yet no current flows in the absence of electric potential across it. Explain the statement with reason.
A large number of free electrons are present in metals yet no current flows in the absence of electric potential across it. Explain the statement with reason.
An electric refrigerator rated $400\, W$ operates $8$ hour per day. What is the cost of the energy to operate it for $30$ days at ₹ $3.00$ per $k W h ?$
An electric refrigerator rated $400\, W$ operates $8$ hour per day. What is the cost of the energy to operate it for $30$ days at ₹ $3.00$ per $k W h ?$
Define resistance of a conductor. State the factors on which resistance of a conductor depends. Name the device which is often used to change the resistance without changing the voltage source in an electric circuit.
Calculate the resistance of $50 \,m$ length of wire of cross $-$ sectional area $0.01$ square $m m$ and of resistivity $5 \times 10^{-8}\, \Omega m$
Define resistance of a conductor. State the factors on which resistance of a conductor depends. Name the device which is often used to change the resistance without changing the voltage source in an electric circuit.
Calculate the resistance of $50 \,m$ length of wire of cross $-$ sectional area $0.01$ square $m m$ and of resistivity $5 \times 10^{-8}\, \Omega m$
$(a)$ Name an instrument that measures electric current in a circuit. Define the unit of electric current.
$(b)$ What do the following symbols mean in circuit diagrams ?
$(c)$ An electric circuit consisting of a $0.5\, m$ long nichrome wire $XY,$ an ammeter, a voltmeter, four cells of $1.5\, V$ each and a plug key was set up.
$(i)$ Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points $X$ and $Y$ and the electric current flowing through $XY.$
$(ii)$ Following graph was plotted between $V$ and.$I$ values What would be the values of $V / I$ ratios when the potential difference is $0.8 V, 1.2 V$ and $1.6 V$ respectively ? What conclusion do you draw from these values ?
$(a)$ Name an instrument that measures electric current in a circuit. Define the unit of electric current.
$(b)$ What do the following symbols mean in circuit diagrams ?
$(c)$ An electric circuit consisting of a $0.5\, m$ long nichrome wire $XY,$ an ammeter, a voltmeter, four cells of $1.5\, V$ each and a plug key was set up.
$(i)$ Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points $X$ and $Y$ and the electric current flowing through $XY.$
$(ii)$ Following graph was plotted between $V$ and.$I$ values What would be the values of $V / I$ ratios when the potential difference is $0.8 V, 1.2 V$ and $1.6 V$ respectively ? What conclusion do you draw from these values ?